Rashida Tlaib, an American of Palestinian descent, and Ilhan Omar are the first two Muslim women elected to Congress
US President Donald Trump came under fire from Democrats and even some members of his own Republican Party on Monday after launching an extraordinary xenophobic attack on four progressive Democratic congresswomen.
The self-styled "squad" of progressive newcomers are representatives Alexandria Ocasio-Cortez of New York, Ilhan Omar from Minnesota, Ayanna Pressley of Massachusetts and Rashida Tlaib from Michigan - all of whom except Omar are American-born.
Ocasio-Cortez, a 29-year-old of Puerto Rican ancestry, is the youngest member of the House, while Pressley is the first African American elected to Congress from Massachusetts.
Tlaib and Omar are the first two Muslim women elected to Congress.
Tlaib is the first American of Palestinian descent elected to the body, while Omar, who fled war-torn Somalia as a child and came to the United States as a refugee, is the first black Muslim woman in the legislature. She wears the hijab.
"All they do is complain," Trump told reporters at a White House event featuring products "Made in America."
"These are people that hate our country," he said of the four lawmakers. "If you're not happy here, you can leave."
Trump also accused the four first-term congresswomen - who are of Hispanic, Arab, Somali and African American origin - of having "love" for US "enemies like Al-Qaeda."
Asked by a reporter whether he was concerned that many people saw his comments as racist, Trump said: "It doesn't concern me because many people agree with me."
Several hours after his remarks, the four women hit back at a news conference.
Pressley condemned Trump's "xenophobic and bigoted" comments and said "we will not be silenced."
Omar said Trump made a "blatantly racist attack" on four lawmakers "of colour." "This is the agenda of white nationalists," she said.
Omar and Tlaib repeated calls for Trump to be impeached.
Democratic congressman Al Green, of Texas, separately said he would bring an impeachment vote to the House floor this month "for bigotry in policy, harmful to our society."
The president first attacked the lawmakers - all but one of whom were born in America - with a series of tweets on Sunday, saying they should "go back" to their countries of origin.
His comments prompted critical reactions from foreign leaders, and outrage at home from Democrats -- while Republicans were initially silent.
On Monday, several of his party faithful began to speak up.
"My view is that what was said and what was tweeted was destructive, was demeaning, was disunifying, and frankly it was very wrong," said Senator Mitt Romney, a Republican from Utah.
"There is no excuse for the president's spiteful comments -- they were absolutely unacceptable and this needs to stop," said Senator Lisa Murkowski, a Republican from Alaska. "We must demand a higher standard of decorum and decency."
Republican Senator Susan Collins of Maine said she disagreed with the policies espoused by the "far-left" Democratic lawmakers, but that Trump was "way over the line."
For Republican Senator Pat Toomey of Pennsylvania, "the citizenship of all four is as valid as mine." He said "they are entitled to their opinions, however misguided they may be."
Texan Will Hurd, the only black Republican in the House of Representatives, told CNN that Trump's behaviour was "unbecoming of the leader of the free world."
And Senator Tim Scott, a black Republican from South Carolina, criticized the president for using "unacceptable personal attacks and racially offensive language."
New Zealand Prime Minister Jacinda Ardern became the latest international leader to condemn Trump's tweets.
"I completely and utterly disagree with him," she told Radio New Zealand, noting that her country welcomed diversity in the corridors of power.
Canadian Prime Minister Justin Trudeau and Britain's Theresa May also expressed disapproval.
Trump's comments appear to be aimed at galvanizing his mostly white electoral base ahead of the 2020 presidential vote - while also stoking racial tensions and divisions among his political opponents.
"With his deliberate, racist outburst, @realDonaldTrump wants to raise the profile of his targets, drive Dems to defend them and make them emblematic of the entire party," said David Axelrod, who served as chief strategist for Barack Obama's two White House campaigns.
In his initial Twitter attack on Sunday, Trump - who before becoming president pushed the racist "birther" conspiracy theory that Obama was not born on US soil - said the congresswomen came from corrupt, poorly managed countries to which they should return.
Ocasio-Cortez, Tlaib and Pressley were all born in the United States while Omar arrived as a refugee from war-torn Somalia, which she fled as a child.
Former vice president Joe Biden, who is seeking the 2020 Democratic presidential nomination, denounced Trump as the most "openly racist and divisive" president in US history.
"Go home to your country? It's sickening, it's embarrassing," Biden said.
Nancy Pelosi, the Democratic speaker of the House of Representatives, has had a tenuous relationship with the four left-leaning congresswomen, but she jumped to their defence.
Pelosi said she was seeking Republicans to co-sponsor a House resolution "condemning the president's xenophobic tweets" and "characterization of immigrants."
Democratic Senator Chuck Schumer of New York said he planned to do the same in the Senate.