This has been CNBC's live blog covering updates on the war in Ukraine. Follow the latest updates here.

Oil prices leaped — exceeding $130 a barrel to touch a 13-year high — on the possibility that the United States and its allies will completely ban Russian oil and natural gas imports.

"We are now talking to our European partners and allies to look in a coordinated way at the prospect of banning the import of Russian oil while making sure that there is still an appropriate supply of oil on world markets," Secretary of State Antony Blinken said in an interview on Sunday.

"That's a very active discussion as we speak," he said.

Separately, U.S. Speaker Nancy Pelosi said the House is "exploring strong legislation that will further isolate Russia from the global economy," including a ban on oil imports and steps to "deny Russia access to the World Trade Organization."

Meanwhile on the ground in Ukraine, Russian forces appear to have made no significant movement over the past day, according to a senior U.S. Defense official. Leading elements of the Russian advance remain outside Kyiv, Kharkhiv and Chernihiv as they're met by strong Ukrainian resistance.

Almost all the military strength that Russia amassed along the Ukraine border prior to invading has now been sent into Ukraine, the Defense official said.

No-fly zone over Ukraine would increase risk of a U.S.-Russia war, defense analyst says

A no-fly zone over Ukraine would "greatly increase" the risk of a war between the U.S. and Russia, according to Ted Galen Carpenter, senior fellow for defense and foreign policy studies at the Cato Institute.

"It's absolutely imperative that the United States resist Zelenskyy's call for a no-fly zone over Ukraine," he told CNBC's "Street Signs Asia" on Monday.

The Ukrainian president has repeatedly asked NATO to establish a no-fly zone over his country, but the U.S. and its allies have so far rejected that request. Setting up a no-fly zone would mean the alliance would have to shoot down Russian aircraft over Ukraine.

"That would greatly increase the danger of a war between the United States and Russia, and we are talking about a war with nuclear implications at that point," Carpenter said.

"I don't think anyone in the United States thinks that Ukraine's security is worth taking that level of risk," he added.

Putin previously said he would consider a third-party declaration of a no-fly zone over Ukraine as "participation of that country in the military action."

— Abigail Ng

Three-way talks underway to send fighter jets to Ukraine

Poland, Ukraine and the United States are in talks on a deal that would get more MiG fighter jets into the hands of Ukraine.

NBC News reported that the deal would involve Poland giving MiG fighter planes to Ukraine, and the United States in turn replacing Poland's fighters with U.S.-made F-16s.

Neither Ukraine nor Russia has established air superiority in their 11-day old war, and Ukraine President Volodymyr Zelenskyy made an urgent request for fighter aircraft during a call with 300 members of Congress on Saturday.

Ukrainian pilots are not trained to fly U.S.-made warplanes. However, Poland and Ukraine both operate MiGs — aircraft designed and made in Russia — that are left over from the days of the Soviet Union.

Ukraine Foreign Minister Dmytro Kuleba over the weekend said warplanes and air-defense systems are his country's "highest demand" as Ukraine faces almost 200,000 Russian troops and their vehicles.

The F-16 is manufactured by General Dynamics, a unit of Lockheed Martin.

—Ted Kemp

U.S. House 'exploring strong legislation' to ban Russian oil

In a letter to Democratic colleagues, Speaker Nancy Pelosi said the U.S. House of Representatives is "exploring strong legislation" to ban imports of Russian oil.

The legislation would "further isolate Russia from the global economy," she wrote.

"Our bill would ban the import of Russian oil and energy products into the United States, repeal normal trade relations with Russia and Belarus, and take the first step to deny Russia access to the World Trade Organization. We would also empower the Executive branch to raise tariffs on Russian imports," she said.

The House will vote on aid to Ukraine this week totaling $10 billion in humanitarian, military and economic support.

—Ted Kemp

U.S. crude oil spikes above $125 per barrel on possible Western ban of Russian oil

U.S. crude oil jumped above $125 per barrel in early trading Sunday evening, as the market continued to react to supply disruptions stemming from the war between Russia and Ukraine and the possibility that the U.S. and its allies and partners could institute a ban on Russian oil and natural gas.

West Texas Intermediate crude futures, the U.S. oil benchmark, surged 8%, at one point topping $130 a barrel, to reach its highest level since mid-2008. Brent crude, the international benchmark, traded 9% higher to $128.60, also the highest price seen since 2008.

"Oil is rising on the prospect for a full embargo of Russian oil and products," said John Kilduff, founding partner of Again Capital. "Already high gasoline prices are going to keep going up in a jarring fashion. Prices in some states will be pushing $5 pretty quickly."

— Tanaya Macheel

Senior U.S. defense official provides latest assessment of the Russian-Ukraine war

A senior U.S. defense official early Sunday evening in Washington, D.C., released an updated assessment of how the war is going in Ukraine.

Among the latest updates:

• The U.S. has observed limited changes on the ground over the past day. Russian forces' continued efforts to advance and isolate Kyiv, Kharkhiv and Chernihiv across the north and east are being met with strong Ukrainian resistance.
• Russian troops remain outside these city centers, though there were no specifics on how far away they were. Russian forces do not appear to have made any significant advances along their lines of attack. The 40-mile long Russian convoy headed for the Ukrainian capital of Kyiv continues to be stalled.
• The U.S. assesses that somewhere near 95% of the combat power Russia had amassed along the border is now in Ukraine.
• The U.S. has observed fighting in the south near Kherson and Mykolaiv, but can't independently verify reporting of Russian forces firing on protesters in Kherson.
• Senior U.S. defense officials have not observed an amphibious invasion in or near Odessa, nor do they believe that one is imminent.
• Fighting continues as the Russians continue to attempt to encircle Mariupol, and there continue to be reports of widespread utility outages (water and electricity).
• The airspace over Ukraine continues to be contested. Ukrainian air and missile defenses remain effective and in use. The Ukrainian military continues to fly aircraft and employ air defense assets.
• The U.S. assesses that both sides still possess a majority of their air defense systems and capabilities.
• As of Sunday, approximately 600 launches of Russian missiles of all sizes have occurred since the invasion began.
• Defense officials believe the Ukrainian people in most parts of the country still have means of communication, access to the internet and the media.

— Terri Cullen

Rally for Ukraine outside the White House

Participants attend a rally protesting the Russian invasion of Ukraine at Lafayette Square across from the White House in Washington, D.C., on March 6, 2022.

— Adam Jeffery

Ukraine's Zelenskyy says 'sanctions are not enough'

Ukraine President Volodymyr Zelenskyy called on world leaders to do more for his country.

"Sanctions are not enough. Because there, they [Russia] did not understand, did not feel, and did not see that the world is in fact decisive and is acting, and in fact wants to stop this war," Zelenskyy said, according to a translation of video posted on his Telegram channel.

Zelenskyy has been imploring Western nations and alliances to take a harsher stance against Russia following the nation's invasion on Ukraine. The leader most prominently has been calling for NATO countries to implement a no-fly zone on Ukraine, a decision that many view could start a world war. NATO denied the request.

Zelenskyy on Saturday, speaking during a bipartisan Zoom meeting with more than 300 lawmakers and staff, said that if nations will not close the airspace, then they should ban Russian-made aircraft. He also called for more aid, such as planes and Stinger anti-aircraft missiles.

— Jessica Bursztynsky

VP Harris on Ukrainians: their bravery is a 'reminder that freedom and democracy can never be taken for granted'

Vice President Kamala Harris commented on the conflict in Ukraine during a public appearance Sunday in Alabama.

"Today, the eyes of the world are on Ukraine and the brave people who are fighting to protect their country and their democracy," she said. "And their bravery is a reminder that freedom and democracy can never be taken for granted by any of us."

Harris spoke from Selma, Alabama, where she was commemorating the 57th anniversary of "Bloody Sunday."

— Samantha Subin

Netflix suspends service in Russia

Netflix is suspending its service in Russia, the company confirmed to CNBC.

"Given the circumstances on the ground, we have decided to suspend our service in Russia," a spokesperson said Sunday afternoon.

The Russian market makes up a relatively small percentage of Netflix's overall numbers. The company has just under 1 million subscribers in Russia, CNBC previously reported.

The streaming service previously stopped projects and acquisitions in Russia after the country began its invasion on Ukraine. It had four Russian-language series in production and post-production. Netflix also declined to comply with Russian rules to carry news channels.

— Jessica Bursztynsky

KPMG, PwC are cutting ties to Russia

KPMG and PricewaterhouseCoopers are cutting ties with their Russian operations in response to the ongoing conflict in Ukraine, the accounting firms said Sunday.

"KPMG has over 4,500 people in Russia and Belarus, and ending our working relationship with them, many of whom have been a part of KPMG for many decades, is incredibly difficult," KPMG wrote in a statement Sunday. "This decision is not about them – it is a consequence of the actions of the Russian Government. We are a purpose-led and values-driven organization that believes in doing the right thing."

PwC's global chairman Bob Moritz also announced in an email to employees Sunday that the firm would cut ties with its Russian operations, The Wall Street Journal previously reported. Moritz also reportedly said the company would halt working with Russian firms or individuals affected by sanctions.

"We know this is the right thing to do, but that doesn't make it easy," he wrote in the email.

In February, PwC said it had more than 750 employees in offices across Ukraine including Kyiv, Dnipro, and Lviv. PwC has 3,000 employees and partners in Russia, the Journal reported.

— Samantha Subin

International volunteers pick-up arms and head to Ukraine

In a report issued by the Ukrainian army stating the creation of a foreign legion unit for international volunteers, Ukrainian President Volodymyr Zelenskyy appealed to foreign nationals to join his army in the fight against Russia.

— Adam Jeffery

Heightened security fears in the Baltic states following Russia's Ukraine invasion

CNBC's Steve Sedgwick reports from Vilnius, the capital and the largest city of Lithuania, where he explains the geography and history of the region, and why it's so concerned regarding recent Russian military aggression and the invasion of Ukraine.

— Matt Clinch

Portion of Goldman Sachs employees move from Russia to Dubai, report says

Some of Goldman Sachs' employees in Russia are moving out of the country and into Dubai, Bloomberg News reported on Sunday.

The move is driven by staff seeking to work from a different location, according to the report, citing a person familiar with the matter. The relocation is reportedly not meant to be permanent.

It wasn't immediately clear how many people are currently working in the Russia office, nor transferring into Dubai.

— Jessica Bursztynsky

TikTok suspends some services in Russia

TikTok said in a statement posted Sunday it would suspend live streaming and new content on its platform in Russia.

It comes after President Vladamir Putin approved changes to Russian law on Friday that could punish anyone spreading "fake" news about the war in Ukraine with a prison sentence of up to 15 years.

Many independent and social media platforms have shut down operations in response to the law. Russian media regulators also blocked access to Facebook on Friday after the social media giant restricted access to several state-affiliated media outlet accounts. Twitter reportedly went dark shortly after.

"TikTok is an outlet for creativity and entertainment that can provide a source of relief and human connection during a time of war when people are facing immense tragedy and isolation," wrote TikTok, which is owned by the Chinese company ByteDance. "However, the safety of our employees and our users remain our highest priority."

China was one of three nations that abstained from voting on a resolution condemning Russia's attack on Ukraine in a United Nations Security Council vote in February.

In-app messaging services will not be affected by the suspension, TikTok added. The company also said it would begin piloting a feature that allows the platform to label content from state-controlled media.

— Samantha Subin 

Irpin mayor says eight people killed by Russian shelling

EDITORS NOTE - THIS POST CONTAINS GRAPHIC CONTENT:

Approximately eight people were killed after Russian forces began shelling on Irpin, the city's mayor Oleksandr Markushyn said in a Facebook post.

Four of those killed were a family consisting of two adults and two children.

The attack came as Ukrainians attempted to flee the area, hoping to escape ongoing the violence. Russian forces have said they're not targeting civilians or civilian infrastructure, but death tolls and damage continue to mount. Sunday's attack could mean Russia is targeting escape routes, the New York Times reported.

Irpin is roughly 15 miles to the capital city of Kyiv.

— Jessica Bursztynsky

American Express suspends operations in Russia

American Express said Sunday it's suspending operations in Russia in response to the country's ongoing invasion of Ukraine.

It joins Mastercard and Visa, which announced Saturday they would also halt operations in Russia.

"One of our company values is to 'Do What is Right,'" the company said in a statement. "This principle has guided us throughout this difficult crisis and will continue to do so, as we stand by our colleagues, customers, and the international community in hoping for a peaceful resolution to this crisis."

Cards issued by Russian banks will no longer work outside of the country, the company said, adding that it would halt operations in Belarus. The company also said it previously paused relationships with banks in Russia that have been impacted by the U.S. and international sanctions.

"Over the past few weeks, we have been working hard to back our colleagues and customers in these countries," American Express said. "While this decision will have an impact on them, we will continue to do what we can to support them."

— Samantha Subin 

Ukrainians wait for trains to flee Lviv

People wait for a train to Poland at the railway station of the western Ukrainian city of Lviv on Sunday, March 6, 2022.

— Adam Jeffery

IAEA says Russia has taken over Zaporizhzhya nuclear power plant in Ukraine

The Zaporizhzhya nuclear power plant in Ukraine is under orders from the Russian commander whose forces took control of the site last week, according to a statement from the International Atomic Energy Agency.

Ukraine informed the agency that regular staff are continuing to operate the plant. Any action of the plant management, including steps related to the technical operation of the six reactor units, will require prior approval from the Russian commander, the IAEA said.

Russian forces have also blocked some mobile networks and the internet, the agency said, citing the Ukrainian intelligence.

Russian troops began shelling the plant on Friday, prompting intense fears of a nuclear dangers.

Radiation levels remained normal as of the Sunday afternoon update.

— Jessica Bursztynsky

Blinken tells Moldova that U.S. will rally against Russian aggression 'whenever and wherever'

U.S. Secretary of State Antony Blinken met with Moldovan President Maia Sandu, reassuring the leader it would rally against Russian aggression "whenever and wherever" that might appear.

The Eastern European country of 2.6 million has been among the most vulnerable, as it's not a member of NATO. The nation on Thursday submitted an application to become a member of the EU.

Some fear repercussions against the country, since Moscow-backed separatists have long held a space of land called Transnistria. Sandu said her administration hasn't seen significant changes in the area where an estimated 1,500 Russian troops are deployed.

"In this region, of course, there is no possibility for us now to feel really safe or secure, especially when we watch what is going on, when we saw all those attacks and the war in Ukraine," Sandu said, according to an interpretation.

So far, Moldova has been focusing on bringing in Ukrainian refugees. More than 250,000 people have crossed into the country since the beginning of the Russian invasion, the president said.

During the meeting, Blinken added the U.S. was providing $18 million in the next few years to "help strengthen and diversify Moldova's energy sector."

"Greater energy security is vital for your sovereignty," he said.

— Jessica Bursztynsky

Russian POWs captured in Kyiv

11 Russian soldiers captured by Ukrainian forces make a press statement on Saturday, March 5, 2022 in Kyiv, Ukraine.

— Adam Jeffery

U.S. and Poland are reportedly in talks to send fighter jets to Ukraine

The U.S. has begun talks with NATO ally Poland on a deal to facilitate the transfer of older, Soviet-era fighter jets from the Polish Air Force to its Ukrainian counterpart, NBC News reports.

Under the potential deal being discussed, Poland would donate its MIG fighters to Ukraine to aid in the battle against invading Russian forces, and the U.S. would help replace them with American-made F-16 jets.

"We are working with the Poles on this issue and consulting with the rest of our NATO allies," a White House spokesperson told NBC News.

The president of Ukraine, Volodymyr Zelenskyy, urged more than 300 U.S. Congress members in a Saturday Zoom call to press for just such a transfer of jets and other military equipment from Poland and Romania. Ukraine's foreign minister, Dmytro Kuleba, repeated the call in a meeting with U.S. Secretary of State Antony Blinken at the Poland-Ukraine border.

In response, Sen. Rob Portman, R-Ohio, and Sen. Jeanne Shaheen, D-N.H., wrote to President Joe Biden calling on his administration "to support aircraft transfers to Ukraine from Eastern European allies." 

A White House spokesperson said the decision was ultimately up to Poland. The Polish embassy in Washington, D.C., did not respond to a request for comment from NBC News.

— Kenneth Kiesnoski

Blinken: U.S. and allies considering banning import of Russian oil, natural gas

Secretary of State Antony Blinken said the U.S. and its allies are considering banning Russian oil and natural gas imports in response to the country's invasion of Ukraine during an interview with CNN's "State of the Union" on Sunday.

"We are now talking to our European partners and allies to look in a coordinated way at the prospect of banning the import of Russian oil while making sure that there is still an appropriate supply of oil on world markets," he said. "That's a very active discussion as we speak."

The U.S. and its allies have not currently imposed sanctions on the country's prominent energy industry, but Blinken said President Joe Biden has met with cabinet members about the subject.

After the U.S. and Saudi Arabia, Russia is the world's third-largest oil producer. It's also the largest exporter of crude oil to global markets.

— Samantha Subin

Ukrainians cross a destroyed bridge to flee Irpin

People cross on an improvised path under a bridge that was destroyed by a Russian airstrike, while fleeing the town of Irpin, Ukraine on Saturday, March 5, 2022.

— Adam Jeffery

Love and war in Kyiv: Ukrainian Territorial Defense wedding

Members of the Ukrainian Territorial Defense Forces Lesia Ivashchenko and Valerii Fylymonov at their wedding during the Ukraine-Russia conflict, at a checkpoint in Kyiv.

— Adam Jeffery

Russia detains at least 3,500 in nationwide protests

At least 3,500 people have been detained across Russia in a series of protests against President Vladimir Putin's invasion of Ukraine, the country's interior ministry said in a statement on Sunday.

"The detainees were taken to the territorial police departments for consideration, the issue of bringing them to justice is being decided," the ministry wrote.

Approximately 5,200 people participated in the protests, according to the statement.

— Samantha Subin

More than 900,000 refugees have crossed into Poland

Poland's border guard agency said more than 922,000 Ukrainians have crossed the border into the country since the start of the Russian invasion on Feb. 24.

The agency added on Twitter that a record one-day number of 129,000 refugees entered the country on Saturday.

Poland, a nation of nearly 38 million people, has been accepting the largest number of Ukrainians so far. Overall, 1.5 million people have left Ukraine since the start of the war, the U.N.'s high commissioner for refugees said earlier in the day.

— Jessica Bursztynsky

Blinken: Ukraine has 'plans in place' if Zelenskyy is killed; U.S. investigating attacks on Ukrainian civilians

Secretary of State Antony Blinken said Ukraine has "plans in place" if Ukrainian President Volodymyr Zelenskyy is killed by Russia during the invasion.

"The Ukrainians have plans in place that I'm not going to talk about or get into any details on to make sure that there is what we would call continuity of government one way or another, and let me leave it at that," he told CBS News' "Face the Nation" on Sunday.

Blinken also told CNN's "State of the Union" that the U.S. has seen "very credible reports" of attacks on Ukrainian civilians, which could potentially be classified as war crimes.

"We've seen very credible reports of deliberate attacks on civilians which would constitute a war crime," Blinken said. "We've seen very credible reports about the use of certain weapons."

The U.S. is currently documenting the incidents and intends to support the "appropriate organizations" as they investigate, he said.

— Samantha Subin

Moody's downgrades Russia's credit rating on rising default risk

Moody's cut its credit rating on Russia and kept a negative outlook, Reuters reported Sunday. The ratings agency cited sanctions that are restricting cross-border payments, including debt payments.

The ratings downgrade as "driven by severe concerns around Russia's willingness and ability to pay its debt obligations," the rating agency said, according to Reuters, which said default risks have increased.

Moody's said the "likely recovery for investors will be in line with the historical average, commensurate with a Ca rating. At the Ca rating level, the recovery expectations are at 35 to 65%," Reuters reported.

— Terri Cullen

Ukraine says Russia has violated the latest cease-fire in Mariupol

Ukrainian Interior Ministry advisor Anton Gerashchenko said Sunday that Russia had once again violated a cease-fire agreement in the city of Mariupol.

In a post on Telegram, Gerashchenko said the situation was a repeat of Saturday, when Russia was accused of continuing to attack the cities of Mariupol and Volnovakha despite a cease-fire agreement.

"Second attempt to create a "green corridor" for civilians in Mariupol again resulted in shellings from the Russian side," according to the post. "Everyone needs to understand that because occupational army kills civilians — there's no security guarantees for 'green corridors.' "

The official did not say whether the planned evacuation of civilians from the city had been canceled.

The city had planned to transport residents from Mariupol to Zaporozhye, a city to the west, during a cease-fire agreed between 10 a.m. and 9 p.m. local time.

On Saturday, planned evacuations from the cities of Mariupol and Volnovakha were canceled after Iryna Vereshchuk, deputy prime minister of Ukraine, said Russia had violated the cease-fire agreement, with fighting continuing in or around both cities.

— Katrina Bishop

Blinken: U.S. considering sending planes to Poland if needed

Secretary of State Antony Blinken says that if Poland sends jets to Ukraine, to join the fight against Russia, the U.S. would consider sending replacement planes to Poland.

Speaking at a press conference in Moldova, he added that it was being considered "very, very actively."

"We are looking actively now at the question of airplanes that Poland may provide to Ukraine and looking at how we might be able to backfill should Poland decide to supply those planes," Blinken said.

"I can't speak to a timeline but I can just say we're looking at it very, very actively."

—Katrina Bishop

Ukraine president: U.S. is preparing new sanctions; Russia plans to bombard Odessa

Ukrainian President Volodymyr Zelenskyy has said the U.S. is preparing new support for Ukraine and new sanctions for Russia.

"I talk to the leaders of many countries every day and every night. There is no hour when Ukraine does not hear what help it will receive. For example, the United States is preparing new support for Ukrainians and new sanctions for Russia," he said Sunday, according to a translation of a televised address.

Zelenskyy also said that Russia was planning to bombard Odessa, the third-largest Ukrainian city and a key port on Ukraine's coast.  

"Russians have always come to Odessa, always felt in Odessa only warmth, only sincerity. And now what? Bombs against Odessa, artillery against Odessa, missiles against Odessa," he added.

"It will be a war crime, it will be a historical crime."

—Katrina Bishop

UK's Boris Johnson outlines a six-point plan for Ukraine

Britain's Prime Minister Boris Johnson has laid out a six-point plan for resolving the Ukraine crisis in a New York Times article, saying the time to act is now.

In the guest essay, entitled "Putin's Act of Aggression Must Fail," Johnson said it was no longer enough to share "warm platitudes" about the rules-based international order. 

"We are going to have to actively defend it against a sustained attempt to rewrite the rules by force and other tools, such as economic coercion. We must restore effective deterrence in Europe, where, for too long, the very success of NATO and of America's security guarantee has bred complacency. What happens in Europe will have profound implications worldwide," he wrote.

In the article, Johnson calls for allies to do the following:

• Mobilize an international humanitarian coalition
• Do more to help Ukraine defend itself
• Maximize the economic pressure on Putin's regime
• Prevent any normalization of Putin's actions in Ukraine
• Be open to de-escalation and diplomacy
• Strengthen "Euro-Atlantic security"

"Ukrainians have bravely defended their country. It is their valor that has united the international community. We can't let them down," Johnson added.

—Katrina Bishop

Over 1.5 million refugees have left Ukraine in last 10 days: UN

Filippo Grandi, the U.N. high commissioner for refugees, says that over 1.5 million refugees have left Ukraine since Russia's invasion of the country began.

He described it as the "the fastest growing refugee crisis in Europe since World War II."

WHO: Attacks on health care facilities in Ukraine have caused deaths, injuries

The World Health Organization confirms that there have been multiple attacks on health care facilities in Ukraine.

Tedros Adhanom Ghebreyesus, director-general of WHO, said on Twitter that the attacks had caused "multiple deaths and injuries."

Ukraine war to last 'months, if not years,' UK deputy prime minister warns

U.K. Deputy Prime Minister Dominic Raab said Sunday that the war in Ukraine could last months, if not years.

Speaking to Sky News, Raab said: "Our mission with our allies is to ensure Putin fails in Ukraine, and it's going to take some time — we're talking about months, if not years — and therefore we have to show some strategic stamina, because this is not going to be over in days."

Mariupol officials say cease-fire to allow civilians to leave is planned for today

Mariupol City Council says that another temporary cease-fire is planned for Sunday to allow civilians to leave the Ukrainian city.

Fighting is due to stop between 10 a.m. and 9 p.m. local time. It was not immediately clear if the cease-fire was underway during this time.

The evacuation of civilians is scheduled to begin at midday, the city said in a post on Telegram.

"Following the route of the humanitarian corridor, you can leave the city by private transport, moving in a column of municipal transport (exclusively by bus)," the city said, according to a translation.

"At the head of the column will be accompanied by the Red Cross. We ask all drivers leaving the city to facilitate the evacuation of civilians as much as possible - take people with you, fill the transport as much as possible."

The safe route — described as a "humanitarian 'green' corridor" — will go from Mariupol to Zaporozhye, a city to the west, with a number of stops along the way.

It comes after planned evacuations from Mariupol and Volnovakha were canceled Saturday due to fears of violence in the cities and on the routes out. Iryna Vereshchuk, deputy prime minister of Ukraine, said Saturday that Russia had violated the cease-fire agreement, with fighting continuing in or around both cities.

The cities have born the brunt of some of the most intense fighting in Ukraine over recent days.

Their location — in Ukraine's extreme southeast corner, near the Russian border, the Sea of Azov and Crimea — makes them strategic targets for Moscow. If they fell to Russia, its troops could join forces with those in Crimea, a peninsula Moscow seized from Ukraine in 2014.

—Katrina Bishop

Putin 'forced to deny' reports that martial law is coming to Russia

President Vladimir Putin was "forced to deny reports" that his government will impose martial law in order to stamp out Russian dissent against the war in Ukraine, according to the U.K. Defence Ministry.

Putin made the denial at an event in Moscow on Saturday local time. Rumors of impending martial law have swirled in Russia for days as the Kremlin tries to control opposition to the war in Ukraine.

Putin on Friday approved changes to Russian law that impose prison sentences of up to 15 years for "fake" news about the war in Ukraine.

"These steps likely reveal the extent of Russia's concern over how the conflict in Ukraine has unfolded and its desire to hide this from the Russian population," the U.K. ministry said in a Saturday intelligence update.

Demonstrators have protested the war in Moscow and elsewhere in Russia despite the threat of arrest or worse.

British newspaper the Guardian reported late last week that a bill was introduced in Russia's legislature, the State Duma, that would forcibly conscript opposition protesters to fight in eastern Ukraine.

—Ted Kemp

Zelenskyy and Biden discuss security, financial support

President Volodymyr Zelenskyy of Ukraine spoke by phone with U.S. President Joe Biden on Saturday evening Washington time, the White House said.

On Twitter, Zelenskyy referred to the conversation as part of a "constant dialogue."

"The agenda included the issues of security, financial support for Ukraine and the continuation of sanctions against Russia," the Ukrainian president said.

Biden initiated the call, the White House said.

Also on Saturday local time, U.S. Secretary of State Antony Blinken and Ukraine's foreign minister, Dmytro Kuleba, briefly met at the Ukraine-Poland border to discuss Western efforts to support Ukraine amid Russia's invasion of the country.

The pair of top diplomats discussed supplying additional weapons to Ukraine and efforts to impose sanctions on Russia to further isolate the country and damage its economy.

—Ted Kemp and Annie Palmer

Visa and Mastercard suspend operations in Russia, citing the invasion of Ukraine

Visa and Mastercard on Saturday said they will suspend all operations in Russia in response to the country's invasion of Ukraine. The move came after Ukraine President Volodymyr Zelenskyy made an impassioned plea during a Zoom call with American lawmakers to restrict the companies' credit card access in Russia.

Visa said effective immediately it will work to cease all Visa transactions within Russia in the coming days. Afterward, the company said, all transactions initiated with Visa cards issued in Russia will no longer work outside the country and any Visa cards issued by financial institutions outside of Russia won't work within the Russian Federation.

"We are compelled to act following Russia's unprovoked invasion of Ukraine, and the unacceptable events that we have witnessed," Al Kelly, chairman and chief executive officer of Visa, said in a statement. "This war and the ongoing threat to peace and stability demand we respond in line with our values."

Mastercard said it would suspend its network services in Russia. Cards issued by Russian banks won't be supported by the Mastercard network, and Mastercard cards issued outside of the country will not work at Russian merchants or ATMs, the company said in a statement.

"As we take this step, we join with so many others in hoping for and committing to a more positive, productive and peaceful future for us all," the company said.

Russia's largest lender, Sberbank Rossii PAO, said the moves announced by Visa and Mastercard would not affect users of the cards it issues in Russia, Reuters reported, citing the Tass news agency.

"These decisions will not affect Sberbank's Visa and Mastercards inside the country," the Russian news agency quoted the bank as saying, Reuters said.

  — Terri Cullen

Zelenskyy calls on Ukrainian citizens to 'go on the offensive'

Ukrainian President Volodymyr Zelenskyy urged citizens of his country to "go on the offensive" against invading Russian troops.

"Every meter of our Ukrainian land won by protest and humiliation of the invaders is a step forward, a step towards victory for our entire state," Zelenskyy said in a video posted on Telegram. "This is a chance to live."

"Ukrainians! In all our cities where the enemy entered. Feel it. Go on the offensive," he added.

Zelenskyy praised the heroism of residents in Kherson, a port city in southern Ukraine that was taken by Russian forces this week. On Saturday, residents gathered to protest the Russian occupation as gunfire rang out, according to one video posted by the Ukrainian Defense Ministry.

Zelenskyy also addressed people in the rebel-held areas of Donetsk and Luhansk, located in southeastern Ukraine. He urged them to fight for Ukraine and reject Russian propaganda.

"Look what Russia has done," Zelenskyy said. "It did it right in front of your eyes. Protect yourself! Otherwise, it will take your life, too."

— Annie Palmer