Trump won 57 percent of white voters in 2016 while Clinton won 37 percent.

Democratic congresswoman Ilhan Omar branded Donald Trump a "fascist" on Thursday as the president sought to distance himself from mocking chants of "Send her back!" directed at the Somali-born lawmaker by his supporters.

"We have said this president is racist, we have condemned his racist remarks," said Omar, one of two Muslim women in Congress. "I believe he is fascist."

Chants of "Send her back!" broke out at Trump's "Make America Great Again" rally in Greenville, North Carolina, on Wednesday night when he attacked Omar and three other ethnic minority Democratic congresswomen known as the "Squad."

Omar received a very different reception when she returned home to Minnesota Thursday night and was greeted by crowds of supporters at the airport.

The president's "nightmare is seeing a Somali immigrant refugee rise to Congress," she said through a megaphone, to shouts of support.

"We are going to continue to be a nightmare to this president, because his policies are a nightmare to us."

Trump claimed to reporters in the Oval Office on Thursday that there was "great energy" at his earlier rally but he was not pleased by the taunts.

"I was not happy when I heard that chant," he said. "I didn't like that they did it, and I started speaking quickly."

Television footage showed, however, that Trump let the chant continue for more than 10 seconds before he resumed speaking.

In a rare move, the Democratic-controlled House of Representatives on Tuesday rebuked Trump for "racist comments" after he said the four should "go back" to their countries of origin if they are not happy in the United States.

But he made it clear at the rally that without a Democratic presidential candidate to focus on yet, he plans to make inflammatory attacks on Omar and her three fellow left-leaning Democrats a centerpiece of his 2020 re-election strategy.

The first-term lawmakers -- all but one of whom, Omar, were born in the United States -- are of Hispanic, Arab, Somali and African-American descent.

'Rallying his base'

To the delight of his thousands of supporters in Greenville, Trump described Omar and the other three as "left-wing ideologues (who) see our nation as a force of evil."

"A vote for any Democrat in 2020 is a vote for the rise of radical socialism and the destruction of the American Dream -- frankly the destruction of our country," Trump said.

The crowd responded to his attacks with cries of "Send her back!" reminiscent of the "Lock her up!" chants directed in 2016 at the Democratic candidate, Hillary Clinton.

Some Republicans have urged Trump to tone down the rhetoric but the president clearly believes -- despite the risk of inflaming racial tensions and widening the partisan divide -- that he has latched on to a winning strategy.

Trump tapped into grievances among white blue-collar and rural Americans to eke out a narrow victory in 2016 and he's hoping to do the same again next year.

"He's rallying his base," said Wendy Schiller, a professor of political science at Brown University. "He thinks this is a way to get them riled up now."

Trump won 57 percent of white voters in 2016 while Clinton won 37 percent.

About 70 percent of the electorate next year is expected to be white. African-Americans, Hispanics and other minorities account for the rest and tend to vote for Democrats.

'Vile'

Several of the Democratic 2020 presidential hopefuls condemned Trump's remarks.

"It's vile. It's cowardly. It's xenophobic. It's racist," said California Senator Kamala Harris.

"These members of Congress -- children of immigrants, just like so many of us -- are an example of exactly what makes America great," said Joe Biden, the former vice president.

Alexandria Ocasio-Cortez, one of the Democratic congresswomen singled out for criticism by Trump, said they will not "go back" on social progress.

"We will not go back to the days of injustice. We will not roll back our rights," she said at a Democratic fundraiser. "We will go forward."

Republican reaction has been more muted but some spoke out.

"The chants at last night's rally were offensive, and I'm glad the President has disavowed them," said Senator Mitt Romney, a Republican from Utah.

"I deeply disagree with the extreme left & have been disgusted by their tone," said Representative Adam Kinzinger of Illinois. "I woke up today equally disgusted -- chants like 'send her back' are ugly, wrong, & would send chills down the spines of our Founding Fathers.

"This ugliness must end, or we risk our great union."

Trump's remarks also came in for criticism from Canadian Prime Minister Justin Trudeau who called them "hurtful," and European Council President Donald Tusk who said the comments were "totally unacceptable."

Neither referred to Trump by name.