US President Donald Trump has sparked outrage by reportedly using crude language to describe foreign countries in an Oval Office meeting.
Mr Trump insists he did not insult Haitians and appeared to deny calling any nations “shitholes”, as was reported, prompting a global outcry.
Democratic Senator Dick Durbin said Mr Trump called African countries “shitholes” and used “racist” language.
But two Republicans present said they could not remember those comments.
Senators Tom Cotton and David Perdue, of Arkansas and Georgia, said they heard the president “call out” what they described as “the imbalance in our current immigration system”.
Amid widespread coverage of his remarks at the private meeting with lawmakers to discuss immigration legislation on Thursday, Mr Trump on Friday tweeted that his language at the meeting had been “tough”. But he added that the words attributed to him were “not the language used”.
Many US media outlets reported the comments on Thursday, quoting witnesses or people briefed on the meeting. The White House did not deny them.
“I cannot believe that in the history of the White House, in that Oval Office, any president has ever spoken the words that I personally heard our president speak yesterday,” Mr Durbin told reporters on Friday.
House Speaker Paul Ryan, a top Republican, said the reported comments were “unfortunate” and “unhelpful.
Hillary Clinton, who lost to Mr Trump in the 2016 presidential election, said the country had been subjected to his “ignorant, racist views of anyone who doesn’t look like him”.
Mr Trump ignored press questions about the issue as he signed a proclamation declaring a holiday in honour of civil rights hero Martin Luther King Jr – as presidents do every year.
He said Americans were celebrating that “self-evident truth” that “no matter what the colour of our skin or the place of our birth, we are all created equal by God”.
What was the context for the comments?
Mr Trump’s reported remarks came as lawmakers visited him on Thursday to discuss a bipartisan proposal that would impose new restrictions on immigration but protect the so-called “Dreamers” – hundreds of thousands immigrants brought to the US illegally as children – from deportation.
Mr Trump was said to have told them that instead of granting temporary residency to citizens of countries hit by natural disasters, war or epidemics, the US should instead be taking in migrants from countries like Norway.
“Why are we having all these people from shithole countries come here?” the Washington Post quoted him as saying, in remarks first reported to be about Haiti, El Salvador and African nations.
Mr Durbin said that when Mr Trump was told that the largest groups of immigrants with Temporary Protected Status (TPS) were from El Salvador, Honduras and Haiti, the president responded: “Haitians? Do we need more Haitians?”
But in another tweet on Friday the president denied that he insulted Haitians.