Donald Trump has suggested that Vice President Kamala Harris decided to "turn Black" for political gain, as he attacked his Democratic White House rival during a combative interaction with African American journalists in Chicago.

The Republican former president's inflammatory comments marked an escalation of the 78-year-old's vitriol against Harris, whom he falsely accused of having identified as Indian but then, "all of a sudden, she made a turn, and she became a Black person."

Harris, 59, has long identified as Black and graduated from a historically Black university.

"So I don't know, is she Indian or is she Black?" asked Trump during a heated interview at the National Association of Black Journalists conference on Wednesday.

Harris later denounced the attacks as "the same old show" of "the divisiveness and the disrespect" from Trump.

The combative remarks by Trump, who has been eager to improve his performance with Black voters, are likely to send shockwaves through the 2024 White House contest.

They come as the former president, convicted two months ago of felony fraud related to hush money payments to a porn star, struggles to formulate a new strategy less than 100 days before the election.

Later Wednesday he held a campaign rally in Pennsylvania, a battleground state where he narrowly survived an assassination attempt earlier this month, and continued the verbal assault on his rival.

"Everything about Kamala Harris's rollout, it's phony," he told the crowd, adding Harris "tried to outbrand a new Southern accent" when she addressed a large rally Tuesday in Atlanta, Georgia.

"The contrast could not be more stark," he said. "On the one hand you have a radical left puppet candidate who is fake fake fake, and on the other hand you have a president who will fight fight fight for America."

Americans 'deserve better'

In her address to a sorority gathering Wednesday in Houston, Texas, Harris slammed Trump's attacks.

"The American people deserve better," she said. "We deserve a leader who understands that our differences do not divide us, they are an essential source of our strength."

Trump's White House bid was thrown into chaos on July 21 when President Joe Biden, 81, withdrew his candidacy, backing Harris as the Democratic nominee.

Since then, Harris has seen her favorability ratings jump and raked in over $200 million in campaign donations.

Trump, who had placed Biden's health at the heart of the election, now finds himself up against someone nearly two decades his junior, a trailblazer who became the country's first Black, female and South Asian-origin vice president. 

The seismic shake-up has forced Trump and the Republicans to recalibrate rapidly, and it appears they are struggling to settle on a line of attack.

As "Lyin' Kamala," "Laughin' Kamala" and "Crazy Kamala" all failed to stick, Trump's broadsides have become increasingly incendiary and untethered to reality.

Over the last week, Trump has falsely accused the vice president of being anti-Semitic -- despite her marriage to a Jewish man, Second Gentleman Doug Emhoff -- and has claimed outrageously that she supports the murder of newborn babies.

'Play toy'

Trump and Republicans have launched more traditional political attacks, highlighting Harris's pivots on positions she took while trying to carve out a lane in the crowded 2020 Democratic presidential nominating contest.

Harris no longer supports abolishing private health insurance or a government buyback scheme for guns. She has also disavowed positions against fracking and in favor of expanding the Supreme Court. 

And Trump suggested in a Fox News interview this week that Harris would be considered weak and "like a play toy" by other world leaders, saying: "They're going to walk all over her."

The messaging appears to have had little impact, as Harris has erased Trump's lead in multiple key battleground states in the days since becoming the presumptive Democratic nominee, according to a new Bloomberg News/Morning Consult poll.

On Wednesday Harris gained the endorsement of more than 100 venture capital investors, including LinkedIn co-founder Reid Hoffman and billionaire Mark Cuban.

In an open letter, they described themselves as "pro-business" and "pro-American dream" and believe that "strong, trustworthy institutions are a feature, not a bug" of a successful system.