US President Donald Trump has stepped up his attacks on four liberal Democrats in Congress, calling on them to apologise as he faces charges of racism.
All are women of colour who have criticised his policies.
"I don't believe the four Congresswomen are capable of loving our Country. They should apologise to America (and Israel) for the horrible (hateful) things they have said," Trump said in a Twitter post on Sunday.
Trump ignited controversy last weekend when he tweeted that the Democratic congresswomen should "go back" to where they came from if they do not like the US.
Three of the lawmakers - Alexandria Ocasio-Cortez of New York, Ayanna Pressley of Massachusetts, and Rashida Tlaib of Michigan - were born in the US.
Ilhan Omar of Minnesota came as a refugee from Somalia and is a naturalised citizen.
The first-term congresswomen, known as "the Squad", have been very critical of Trump and have also challenged their own Democratic leadership.
Donald Trump launched an attack on Alexandria Ocasio-Cortez an her fellow Democrats last week. Source: Getty, AAP
Elijah Cummings, the Democratic chairman of the House of Representatives Oversight Committee, denounced Trump's latest attack and said he had "no doubt" that Trump was a racist.
"These are folks and women who love their country and they work very hard and they want to move us towards that more perfect union that our founding fathers talked about," Cummings, who is African-American, said on ABC's This Week.
"So when you disagree with the president, suddenly you're a bad person. Our allegiance is not to the president. Our allegiance is to the Constitution of the United States of America and to the American people."
The Democratic-led House of Representatives passed a resolution on Tuesday that said the House "strongly condemns President Donald Trump's racist comments." The symbolic measure was aimed at shaming Trump and the Republicans who stood by him.
Unbowed, Trump launched a blistering critique of Omar during a rally in North Carolina on Wednesday night, pausing when the crowd erupted into chants of "Send her back."
After some fellow Republicans denounced that language, Trump said the next day he did not agree with the chants. On Friday, however, he defended the North Carolina crowd as "incredible patriots".
Omar accused Trump of "spewing fascist ideology".
Ocasio-Cortez said he intentionally egging on the vitriol.
"Rollback the tape ... He relished it. He took it in and he's doing this intentionally," she said on Saturday at a town hall meeting on immigration in New York.
US Senator Cory Booker, who is seeking the Democratic presidential nomination, said on Sunday Trump was "worse than a racist".
"He is actually using racist tropes and racial language for political gain," Booker said on CNN's State of the Union.
Stephen Miller, Trump's top immigration adviser, said the president made clear he disagreed with the "Send her back" chants.
"The core issue is that all the people in that audience, and millions of patriotic Americans all across this country, are tired of being beat up, condescended to, looked down upon, talked down to by members of congress on the left in Washington DC, and their allies in many quarters of the media," he said on Fox News Sunday.
