This was CNBC's live blog tracking developments on the war in Ukraine on Nov.28, 2023. See here for the latest updates.

Finland is set to shut its entire border with Russia this week, the government said on Tuesday. The border will remain closed until Dec. 13, according to a government statement.

Last week Finland had closed all but one of its border crossings with Russia with the goal of halting an inflow of asylum seekers from the country. The Finnish government has repeatedly suggested that the refugees were guided to the border by Russian authorities.

Close to 1,000 people from countries that are not Finland or Russia have entered Finland since August, and most of them have sought asylum in Finland, the government said Tuesday.

"Russia has been not only letting through migrants or third country citizens without valid documentation, over the border toward Finland, but also they have been mobilizing people to access Finland and the European Union through that route," Finnish Foreign Affairs Minister Elina Valtonen told CNBC's Silvia Amaro on Tuesday.

Russia's approach was a "hybrid operation" she said, adding that Finland had "responded accordingly" as a signal that the government "can't accept this phenomenon to take place."

Meanwhile, southern Ukraine and Russia continue to be battered by bad weather, with huge winter storms causing widespread power cuts, losses of water supplies, mass flooding, traffic chaos and destruction. Heavy fighting carries on along the front line in Ukraine, nonetheless.

There have been a number of deaths and injuries as a result of a surge in severe weather in recent days, with snowstorms and high winds hitting southern regions of Ukraine particularly hard, as well as Russian-occupied Crimea and southern Russia — especially its Black Sea coastal area.

Germany is increasing its military support for Ukraine: Foreign minister

"We are not only keeping up our military support for Ukraine's self defense, but we are increasing it by 8 billion euros [$8.79 billion]," Annalena Baerbock, Germany's foreign minister, said Tuesday in response to a question asked by CNBC's Silvia Amaro.

Baerbock added that the NATO-Ukraine forum — scheduled as part of the ongoing NATO meeting in Brussels — also makes clear "that the security and the peace in Ukraine is also the insurance for peace in Europe."

— Sophie Kiderlin

Russia conducting a 'hybrid operation' at borders, Finnish foreign minister tells CNBC

Russia has been allowing migrants without valid documents through to the Finnish border, as well as "mobilizing" people toward Finland and the European Union, Finland's minister for foreign affairs Elina Valtonen told CNBC's Silvia Amaro on Tuesday.

"We consider this to be a hybrid operation by Russia," she said, adding that Finland had "responded accordingly" by deciding to shut its entire border with Russia.

"We hope that Russia goes back to normal where they respect our treaties," Valtonen said. If treaties continue to be disrespected by Russia, borders may remain closed, she added.

Border closures may also impact people who live across the two countries, and diplomatic missions that may otherwise use the crossings to come into the West, she added.

"I think this just goes to show that Russia, in its current state, is using all possible means to cause trouble," Valtonen said.

She also addressed Ukraine's application to join NATO, saying Finland believed Ukraine's "rightful place is in NATO in the future," while pointing out that the alliance cannot accept new members if they are actively involved in a war.

"Whatever the steps are we can take to advance Ukraine's membership in NATO in the future we will take those steps," Valtonen said.

She also reiterated support for Ukraine in its "fight for freedom."

— Sophie Kiderlin

Finland to close entire border with Russia

Finland will shut its entire border with Russia, Elina Valtonen, Finland's minister for foreign affairs, confirmed to CNBC.

Only goods will be able to pass between the two countries. Finnish media said the closure will last for two weeks.

Finland had previously shut all but one of its border crossings to Russia in order to stop an influx of refugees, which the Finnish government has suggested were aided by Russian authorities.

Russia has reacted critically to Finland's decision so far, with a Kremlin spokesperson describing it as a path of confrontation and a big mistake last week.

— Sophie Kiderlin

Norway watching Russian border situation closely, minister says

Norway is watching its border with Russia closely following complaints by its neighbor Finland that Russia was weaponizing immigration and sending asylum seekers to its border crossing points.

Finland has since taken the decision to close all but one of its most northern border crossing points with Russia, accusing Moscow of facilitating migrants traveling to its border points in a bid to destabilize its neighbor and undermine its national security. Russia denied the accusation last week. Estonia and Latvia have also made similar accusations, however.

Espen Barth Eide, foreign minister of Norway, said his country had not yet seen evidence of similar incidents at its own border with Russia, which is far smaller and only has one crossing point open.

"We haven't seen this yet on our border but we follow this closely because we work closely with our Finnish partners," Barth Eide told CNBC's Silvia Amaro in Brussels Tuesday.

"They report a significant increase in third-nation citizens that are coming via Russia to their border, clearly orchestrated by Russia to create a hybrid pressure on Finland," he said.

Finland joined NATO earlier this year, ending decades of military non-alignment it had adhered to since 1945.

— Holly Ellyatt

U.K. looks to galvanize support for Ukraine at NATO meeting

The U.K. is looking to galvanize support for Ukraine at a meeting of NATO foreign ministers on Tuesday, and between NATO and the Ukraine Council on Wednesday.

David Cameron, the U.K.'s former prime minister and recently appointed foreign minister, is attending his first NATO meeting in Brussels this week in his new role.

The Foreign, Commonwealth and Development Office released a statement saying Cameron would "underline that the UK remains firmly behind Ukraine in the face of Russian aggression, urging Allies not to waver in their support."

Cameron is also due to lay out the need for Sweden's urgent accession to the NATO alliance, "stating that the agreement would mark a critical step forward in strengthening peace and stability in Europe."

Sweden's accession has been delayed due to wrangling with current NATO member Turkey, which has accused Sweden of harboring individuals that Ankara considers to be militants, such as the pro-Kurdish PKK group. Sweden says it has addressed Ankara's security concerns by changing terrorism legislation.

"NATO keeps over one billion people safe and secure. And nearly 75 years on, the alliance is stronger than ever," Cameron said in a statement released by the Foreign, Commonwealth and Development Office.

"Putin first believed that NATO would be divided and that Ukraine would crumble. Now he believes he can wait out his war in Ukraine. He was wrong then and he is wrong now," he added.

"Together, the U.K. and our NATO allies will never turn a blind eye to Russian aggression. The U.K. will continue to be a steadfast supporter of Ukraine and a champion for European peace and stability."  

— Holly Ellyatt

Russia, as chair of Big Five nuclear powers, pushes meetings into 2024

Russia, current chair of the "Big Five" nuclear-armed states, will not convene any meetings this year but has presented the group with a schedule for 2024, Deputy Foreign Minister Sergei Ryabkov told reporters on Tuesday, according to Russian news agencies.

Russia took over coordination of the group from the U.S. in August.

The "Big Five" are the veto-wielding permanent members of the U.N. Security Council, and also include China, France and Britain.

"We have outlined our proposals on the agenda and the rough schedule, and can apparently expect to receive feedback from other members of the Five," Ryabkov was quoted as saying.

"But in any case, the coordinator's program will all take place next year."

— Reuters

Wife of Ukraine's military intelligence chief in hospital following suspected poisoning

The wife of Ukraine's military intelligence chief has been admitted to hospital with suspected poisoning, Ukrainian media reported Tuesday.

Sources in the Ukrainian intelligence community told the Kyiv Post news outlet that Marianna Budanova, the wife of Ukraine's head of intelligence, Kyrylo Budanov, had been poisoned.

When asked to confirm reports that Budanova had been taken ill, a source in Ukraine's Defense Intelligence was quoted as telling the Kyiv Post: "Unfortunately this is true."

The Babel news outlet said its intelligence sources had informed it that Budanova had been "poisoned with heavy metals."

Budanova's condition in hospital is unknown but Babel reported that "the course of treatment is now being completed, and then there will be a check-up by the doctors," quoting an unnamed source. Budanova had been diagnosed with heavy metal damage.

"These substances are not used in any way in everyday life and military affairs. Their presence may indicate a purposeful attempt to poison a specific person," the intelligence agency said.

Media outlets said the suspected poisoning was being investigated and treated as an attempted assassination.

— Holly Ellyatt

3,000 additional Chechen fighters to be sent to Ukraine, leader says

Chechen leader Ramzan Kadyrov said an additional 3,000 Chechen fighters will be sent to fight in Ukraine.

"To solve the tasks set by our Supreme Commander-in-Chief Vladimir Putin, we will not spare any effort or resources," Kadyrov said on Telegram Monday, adding: 

"This position is shared with me by another three thousand worthy Chechen soldiers who have begun service as part of new units of the Russian Ministry of Defense and the Russian National Guard."

He said two new regiments subordinate to Russia's defense ministry had been created, called "AKHMAT-Russia" and "AKHMAT-Chechnya." Kadyrov said most of the troops have battle experience and "the best equipment and modern weapons." 

"In addition, the guys are highly combative and very motivated to achieve results."

Chechen fighters have a fierce reputation and one gained in two wars fought against Russia in the 1990s and early 2000s when the Chechen Republic sought independence from Russia. Times have changed since then, however, and Kadyrov is a Putin loyalist.

Kadyrov said the 3,000 Chechen personnel were " the best of the best" and described them as "the ones who deserve to be the loyal foot soldiers of our unsurpassed leader Vladimir Putin!"

— Holly Ellyatt

Russian forces continue efforts to encircle Avdiivka

Russian forces are continuing efforts to encircle and capture the town of Avdiivka in eastern Ukraine, according to the head of the town's military administration.

Avdiivka in Donetsk has become a focal point of intense fighting in recent weeks with Russian forces anxious to capture the strategically-important town in a bid to capture more of the wider Donbas region.

Vitaliy Barabash, head of Avdiivka's military administration, said Tuesday that "things in the Avdiivka sector have become even tougher," he told the media outlet Espreso TV, according to comments reported by Sky News.

"The intensity of clashes has been increasing for some time," he said, adding: "The Russians have opened up two more sectors from which they have begun making assaults — in the direction of Donetsk and in the so-called industrial zone. The enemy is attempting to storm the city from all directions."

Ukraine's General Staff said Tuesday morning that its forces continue to defend the city even though "the enemy does not abandon attempts to surround Avdiivka."

"Our soldiers are steadfastly holding the defense, causing the occupiers significant losses," the military added. CNBC was unable to verify developments on the ground.

— Holly Ellyatt

Russian court extends detention of U.S. reporter Gershkovich

A Russian court said on Tuesday it had extended the detention of Evan Gershkovich, a Wall Street Journal reporter who is awaiting trial on espionage charges he denies, until Jan. 30, 2024.

Gershkovich, a U.S. citizen, was detained by the Federal Security Service (FSB) on March 29 in the Urals city of Yekaterinburg on charges of espionage that carry up to 20 years in prison.

"The court ruled to extend the term of detention of Gershkovich, accused of a crime under Article 276 of the Criminal Code of the Russian Federation, for up to 10 months, that is, until January 30, 2024," Moscow's Lefortovo district court said.

Gershkovich denies the charges.

He is the first U.S. journalist to be detained on spy charges in Russia since the Cold War. Russia said Gershkovich was caught "red-handed" while the FSB, the main successor to the Soviet-era KGB, said he was trying to obtain military secrets.

The Wall Street Journal and Dow Jones say that Gershkovich was simply doing his job in Russia and deny the espionage charges. The Journal and Dow have repeatedly demanded that Russia release him, to no avail.

"Evan has now been unjustly imprisoned for nearly 250 days, and every day is a day too long," The Journal said in a statement.

"The accusations against him are categorically false and his continued imprisonment is a brazen and outrageous attack on a free press, which is critical for a free society. We continue to stand with Evan and call for his immediate release."

— Reuters

Snowstorms and high winds cannot stop military activity entirely, analysts say

Heavy fighting continues along the front line in Ukraine, against a backdrop of severe weather including snowstorms and high winds that have caused widespread damage to infrastructure, power and water supplies.

"A cyclone in the Black Sea and southern Ukraine caused infrastructure damage in many areas of coastal southern Russia and occupied Ukraine and is impacting the tempo of military operations along the frontline in Ukraine, but has notably not stopped military activity entirely," analysts at the Institute for the Study of War noted in an analysis report on Monday.

"Russian sources posted images and footage of the impact of the cyclone on civilian and transportation infrastructure in coastal areas of Krasnodar Krai, including near Sochi, Anapa, Gelendzhik, Novorossiysk, and Taupse," the ISW said.

"Ukrainian and Russian sources also noted that coastal areas of occupied Crimea, occupied Kherson Oblast, and much of Odesa Oblast were heavily impacted by heavy snow and high winds, leaving large swaths of the population without electricity."

The ISW said that Ukraine's navy had noted that dangerous weather in the Black Sea had forced Russia to return all of its naval vessels and missile carriers to their base points.

"Several sources also reported that the storm damaged rail lines in coastal areas, which may have logistical ramifications for Russian forces in occupied Crimea and southern Ukraine."

Ukraine's general staff reported on Tuesday morning that Russian forces continued to launch widespread "missile and air strikes ... firing multiple launch rocket systems not only at the military, but also at numerous civilian targets across Ukraine." It said there had been 84 combat engagements between Russian and Ukrainian forces in the past 24 hours.

CNBC could not independently verify developments on the ground.

— Holly Ellyatt

Ten people die in Ukraine snowstorms, interior minister says

Ten people have died in snowstorms in Ukraine, Interior Minister Ihor Klymenko said on Tuesday.

Icy winds and storms have swept in since Sunday, cutting power and blocking roads, particularly in the south.

"As a result of worsening weather conditions, 10 people died in Odesa, Kharkiv, Mykolaiv and Kyiv regions," Klymenko wrote on the Telegram app.

"Twenty-three people were injured, including two children," he added.

A total of 411 settlements in 11 regions had lost power, and more than 1,500 vehicles had to be rescued, Klymenko said.

— Reuters

Storms continue to batter Ukraine and Russia, causing deaths and injuries

Southern Ukraine and Russia continue to be battered by extreme weather, with storms causing widespread power cuts, losses of water supplies, mass flooding, traffic chaos and destruction.

There have been a number of deaths and injuries as a result of a surge in bad weather in recent days, with storms hitting southern regions of Ukraine particularly hard, as well as Russian-occupied Crimea and southern Russia — especially its Black Sea coastal area.

Ukrainian President Volodymy Zelenskyy said in his nightly address Monday that almost 1,500 settlements in 17 regions across the country had lost power and that "engineers are working everywhere to restore supplies."

"As soon as this is possible, every city, every village will receive electricity. Currently, hundreds of people and hundreds of units of equipment are working around the clock ... the State Emergency Service of Ukraine. The National Police, the National Guard, and utilities are involved."

Zelenskyy said that five people are now known to have died during the storms, most of whom were in the southern Odesa region. At least 19 other people have been injured, he added.

Russian media is also reporting on the scale of the destruction caused by the storms and what it described as a hurricane waging across southern Russia.

Four people have died and more than 20 have been injured, news agency Tass reported, while almost two million people have been left without electricity because of the bad weather. 

"In some regions, water supply and urban transport have been disrupted. Regional authorities are organizing work to overcome the consequences of the disaster and are preparing for worsening weather, which forecasters and emergency services" are warning of, Tass said.

Russian-occupied Crimea has been particularly badly hit, with states of emergency declared in 10 of the peninsula's municipalities. Hurricane wind speeds reached 144 km/h (or almost 90 miles per hour) in Crimea, Tass reported.

The Russian Ministry of Emergency Situations told the Tass news agency that 600 incidents had been logged in more than 300 settlements in Crimea. The ministry was reported as saying that 995 people had to be evacuated as a result of bad weather, with 179 children among them. 

— Holly Ellyatt

Photos show storms in Ukraine and Russia

Storms have brought flooding and heavy snowfall to parts of Ukraine, Russian-occupied Crimea and Russia in recent days. Multiple casualties as well as road and infrastructure chaos have been reported.

— Sophie Kiderlin

Russia is willing to put a lot of effort into this war, NATO warns

Wars tend to last longer than people expect, NATO's secretary general told CNBC, warning that Russia's invasion of Ukraine had shown Moscow had no intentions of capitulating.

"What we have seen is that Russia is willing to put a lot of effort into this war. They're ramping up [weapons] production and they're also sacrificing soldiers in large numbers," Jens Stoltenberg told CNBC's Silvia Amaro in Brussels on Monday.

"We need to be prepared for the long haul," he added. "Yes, it has a price, but the price of not supporting Ukraine is much higher than the price of supporting Ukraine."

— Holly Ellyatt

Three dead as storm hits Crimea and Russia's Black Sea coast

Fierce storms killed three people on the Russian and Crimean Black Sea coast on Monday, with hundreds evacuated.

State news agency TASS reported that one person had been killed in the resort city of Sochi, another on the Russian-held Crimean peninsula, and a third person onboard a vessel in the Kerch Strait, which separates Crimea from the Russian mainland.

Storms have been raging in the Black Sea since Friday.

Video published online showed large waves sweeping over the seafront in Sochi, and carrying away cars. In the Crimean town of Yevpatoriya, streets were flooded.

The Russian-installed governors of Crimea and Sevastopol, both of which Moscow seized and unilaterally annexed from Ukraine in 2014, declared states of emergency.

Russia's emergency services ministry said it had evacuated more than 350 people. And the Energy Ministry said bad weather had left about 1.9 million people without electricity on Monday morning in the southern Russian regions of Dagestan, Krasnodar and Rostov, as well as Crimea and the regions of Ukraine that Russia unilaterally said it had annexed last year.

In the Russian port of Novorossiysk, the Caspian Pipeline Consortium and Russia's Transneft state oil pipeline company announced a halt to loadings due to weather conditions.

— Reuters

Storm chaos continues across Ukraine, south hit worst

Heavy snowstorms continue to rage across Ukraine, with the southern port of Odesa seeing some of the most extreme weather and 1.5 meters of snow.

The Kyiv-Odesa highway is closed, a 100-meter-long pipe of a boiler-house collapsed in the city and 71 car accidents took place in the region over the past 24 hours, NBC News reported.

Over the past 24 hours, Ukraine's State Emergency Service reported the following:

• 892 vehicles had to be towed
• 103 fallen trees were removed
• Traffic is blocked on 14 highways
• 2,019 settlements are currently experiencing power blackouts
• There are about 1,370 cargo vehicles in temporary parking areas
• 1,525 rescuers and 402 pieces of equipment are at work on the ground

— Holly Ellyatt

Bad weather grips Ukraine, causing power cuts and traffic chaos

Severe weather in Ukraine has made conditions "extremely difficult" in a large part of of the country, with snowstorms causing widespread power cuts.

Ukraine's State Emergency Service said Sunday that 386 settlements in 10 regions were disrupted by extreme weather conditions, including snowstorms that trapped motorists, cars and trucks and brought down trees on major roads.

Ukraine's President Volodymyr Zelenskyy said Sunday evening that "weather conditions are extremely difficult in a large part of our country" and that southern regions were experiencing considerable problems, Zelenskyy said in his nightly address.

"I ask all citizens of Ukraine in areas where bad weather prevails: please be as careful as possible ... As soon as possible, our power engineers will restore electricity supply to all cities and villages that are currently experiencing a temporary blackout due to bad weather," he said.

Poor weather is already affecting conditions on the battlefield but fighting remains intense, Zelenskyy said.

"Intense fighting does not stop for a single hour in the Donetsk directions, in the Kharkiv region – the Kupyansk direction. Our soldiers are also holding positions in the south of the country: this is the Zaporizhzhia region, this is our Kherson region," he said.

— Holly Ellyatt

A win for Putin would be a 'tragedy' for Ukrainians, NATO chief says

NATO's Secretary-General Jens Stoltenberg told CNBC it would be a "tragedy" for Ukrainians if Russian President Vladimir Putin wins the war.

Victory would also send a dangerous message to other authoritarian leaders, he warned.

Speaking as NATO foreign ministers meet on Monday to discuss developments in the war and what further support Ukraine needs, Stoltenberg said it would "be a tragedy for Ukrainians if President Putin wins but also dangerous for us."

"The message sent to authoritarian leaders, in Moscow but also in Beijing, would be that when they use military force and invade another country, they get what they want. Therefore we will be more vulnerable if President Putin wins so it's in our security interests to support Ukraine," he told CNBC's Silvia Amaro in Brussels.

Concerns have grown recently that public support for continued military funding for Ukraine has declined. Political shifts in Europe have also heralded new leadership in a number of countries that is more skeptical about continued support for Kyiv.

Stoltenberg said bipartisan support for Ukraine remained strong in the U.S., despite some rumblings of Republican discontent over military aid. The U.S. has committed around $44.2 billion in security assistance to Ukraine since the beginning of Russia's unprovoked invasion in February 2022.

"I'm absolutely confident that the United States understands that it's dangerous for the United States if President Putin wins in Ukraine," he said.

— Holly Ellyatt

Read CNBC's previous live coverage here:

Storms bring chaos to Ukraine and Russia; NATO says victory for Moscow would be a 'tragedy'