• Donald Trump cast doubt on the identity of Vice President Kamala Harris during a combative appearance at the National Association of Black Journalists' annual convention in Chicago.
• Trump asked the crowd, "is she Indian or is she Black?" and claimed she "became a Black person."
• Asked about controversies tied to his running mate JD Vance, Trump said, "The choice of a vice president makes no difference."

Donald Trump's appearance Wednesday at the National Association of Black Journalists' annual convention in Chicago almost immediately went off the rails, as the Republican presidential nominee cast doubt on his rival's ethnicity and clashed with members of the panel.

ABC News senior congressional correspondent Rachel Scott, one of three journalists interviewing Trump before a live audience, began by asking why Black voters should trust him in light of his prior attacks on Black reporters.

Trump lashed out, calling the introduction "very rude" and saying the question was "disgraceful" and asked in a "horrible manner."

"I love the Black population in this country," he said, claiming, "I have been the best president for the Black population since Abraham Lincoln."

Trump was then asked to clarify what he meant when, in prior remarks, he referred to "Black jobs."

"A Black job is anybody that has a job," he explained.

"That's what it is. Anybody that has -- they're taking the employment away from Black people," he went on, apparently referring to undocumented immigrants. "They're coming in, and they're coming in, they're invading."

Trump also drew a loud response from the audience when he was asked about his supporters calling his likely election rival, Vice President Kamala Harris, a "DEI hire."

"She was always of Indian heritage and she was only promoting Indian heritage," Trump replied. "I didn't know she was Black until a number of years ago, when she happened to turn Black and now she wants to be known as Black."

"So I don't know, is she Indian or is she Black?" he said. "She was Indian all the way, and all of a sudden, she made a turn and she became a Black person."

Later, Trump responded to a swell of criticism surrounding his running mate, Sen. JD Vance of Ohio, whose past comments about childless Americans have resurfaced following his nomination.

Vance's comments include denigrating key Democrats as "childless cat ladies" and suggesting that Americans with children should get more votes than those who do not have kids.

Trump said of Vance, "He thinks the family experience is a very important thing."

But when he was asked about whether parents should get more votes, Trump said, "Well, no."

Trump also did not directly answer when he was asked by Fox News anchor Harris Faulkner if he believed Vance was ready to potentially serve as president on Day 1, if he had to.

"Historically, the vice president in terms of the election does not have any impact," Trump said. "The choice of a vice president makes no difference."

"You're voting for the president," he said. "You're voting for me. If you like me, I'm gonna win."

The event, which was billed as an hourlong question-and-answer session, began more than an hour late and ended after less than 45 minutes. One of the journalists on the panel suggested that the Trump campaign was calling time on the event.

The Republican nominee spoke with Scott, Faulkner and politics reporter Kadia Goba of Semafor.

Trump's opponents, including the White House and the Harris campaign, excoriated Trump's remarks questioning the de facto Democratic nominee's racial identity.

"It's repulsive, it's insulting," White House press secretary Karine Jean-Pierre said in a briefing Wednesday afternoon.

A source familiar with the Harris campaign's thinking told NBC News that Trump "is completely unhinged ... He cannot help himself."

Harris is not attending the five-day convention, but the NABJ on Wednesday said that it is in talks with her team about scheduling either a virtual or in-person Q&A session in September.

The convention appearance gave Trump, who won just 12% of Black voters in his 2020 election loss to President Joe Biden, an opportunity to directly appeal to voters of color on a major platform.

But he may have more trouble courting these voters in a competition against Harris, who is the first Black person, first woman and first person of South Asian descent to serve as vice president.

His combative performance Wednesday afternoon may not win him any new converts.

Some polls show that Harris has more support among Black, Latino and young voters than Biden did before she replaced him as the de facto Democratic nominee.

On Tuesday, a new Bloomberg/Morning Consult survey of key swing states found that Harris has effectively eliminated Trump's lead in the seven battlegrounds likely to determine which candidate wins the Electoral College.

The NABJ's booking of Trump had spurred a backlash within the organization even before he took the stage.

Convention co-Chair Karen Attiah resigned her position on the eve of the event, writing in a social media post, "To the journalists interviewing Trump, I wish them the best of luck."

NABJ leaders defended the move, saying it was in line with the group's practices stretching back to the mid-1970s.

Although Biden had planned, when he was still a candidate, to attend the event, a person familiar with Harris' plans told NBC News on Tuesday that the vice president could not fit a convention appearance into her schedule this week.

Harris' overlapping plans include attending the funeral of the late Rep. Sheila Jackson Lee, D-Texas, and the ongoing process of selecting a running mate.

This is developing news. Please check back for updates.