Video report by ITV News Reporter Olivia Kinsley
The UN has joined African nations and Haiti in condemning "shocking, shameful... and racist" remarks reportedly made by Donald Trump during an Oval Office meeting about revamping rules affecting entrants from Africa and Haiti.
The US President reportedly questioned why America should allow more immigrants from "s***hole countries", the Washington Post reported.
Mr Trump has denied using foul language.
The United Nations human rights office said the President's reported use of an expletive to describe African countries could "potentially damage and disrupt the lives of many people", while the African Union continental body said it was "frankly alarmed.
Meanwhile, Haiti has branded the remarks "racist" and said it was "deeply shocked and outraged" by them.
A spokesperson for the Haitian Government continued that the remarks were "insulting and reprehensible" and "in no way reflect the virtues of wisdom, restraint and discernment that must be cultivated by any high political authority."
It added that the comment as reported "reflects a totally erroneous and racist view of the Haitian community and its contribution to the United States".
UN spokesperson Rupert Colville said: "You cannot dismiss entire countries and continents as 's***holes'."
He continued that the reported comments were "shocking and shameful", adding: "I'm sorry, but there's no other word one can use but racist."
Mr Colville worried that the reported remark could endanger lives by potentially fanning xenophobia: "It legitimises the targeting of people based on who they are. This isn't just a story about vulgar language, it's about opening the door to humanity's worst side."
He added that the reported comments "go against the universal values the world has been striving so hard to establish since World War Two and the Holocaust".
Ebba Kalondo, a spokesperson for the African Union added that the reported comments "fly in the face of all accepted behaviour and practice".
Ms Kalondo said: "Given the historical reality of how many Africans arrived in the United States as slaves, this statement flies in the face of all accepted behaviour and practice.
"This is particularly surprising as the United States of America remains a global example of how migration gave birth to a nation built on strong values of diversity and opportunity."
Mr Trump is said to have made the remark as two senators described details of a bipartisan compromise that would extend protections against deportation for hundreds of thousands of young immigrants and strengthen the border.
Later the president appeared to tweet a denial, acknowledging the language he used in the meeting had been "tough", but adding "this was not the language used".
During the meeting, Mr Trump specifically questioned why the US would want to admit more people from Haiti, which in 2010 was struck by a devastating earthquake which killed an estimated 300,000 people and displaced a further one million.
According to the Washington Post report he also mentioned Africa and asked: “Why are we having all these people from s***hole countries come here?"
When asked about the remarks, White House spokesman Raj Shah did not deny they had been made.
"Certain Washington politicians choose to fight for foreign countries, but President Trump will always fight for the American people," he said.
House Speaker Paul Ryan described the remarks as "very unfortunate", while the US ambassador to Panama, John Feeley, quit in protest.
As the uproar grew, Mr Trump tweeted again that he "never said anything derogatory about Haitians" and claimed to have "a wonderful relationship with Haitians".
In fact, Mr Trump has spoken positively about Haitians in public.
During a 2016 campaign event in Miami, he said "the Haitian people deserve better" and told the audience of Haitian-Americans he wanted to "be your greatest champion, and I will be your champion".
However, the New York Times reported in December that during a June meeting the president had said Haitians "all have Aids".
And late last year the Trump administration announced it planned to end a temporary residency permit programme that allowed nearly 60,000 citizens from Haiti to live and work in the US following the 2010 earthquake.
The meeting where Mr Trump made his comments had been aimed at ending a protracted and bitter dispute over protecting the "Dreamers".
During the meeting, Dick Durbin, of Illinois, the chamber's No 2 Senate Democratic leader, explained that as part of a deal, a lottery for visas that has benefited people from Africa and other nations would be ended, though there could be some other way for them to apply.
Mr Durbin said people who had fled to the US after disasters hit their homes, in places including El Salvador, Guatemala and Haiti, would be allowed to stay in the country.
Mr Trump said the US should allow more entrants from countries like Norway instead, after the president met this week with Norwegian Prime Minister Erna Solberg earlier this week.
Senators had hoped Mr Trump would back the proposal, but the White House later rejected it, plunging the issue back into uncertainty just eight days before a deadline that threatens a government shutdown.