Facing strong condemnation at home and abroad, including from Christians, Donald Trump last night denied using the word 's***hole' to describe Haiti and African countries, but kept up criticism of a Senate immigration plan that he said would force the US to admit people from countries that 'are doing badly'.

Trump reportedly made the remarks at a White House meeting on immigration on Thursday. US Democratic Senator Dick Durbin, who attended the gathering, told reporters on Friday that Trump used 'vile, vulgar' language, including repeatedly using the word 's***hole' when speaking about African countries.

The Republican President's comments were decried as racist by African and Haitian politicians, by the United Nations human rights office and by US lawmakers from both major parties.

Trump, who has been accused of racism over several issues since he took office a year ago, sought to row back the comments on Friday, saying on Twitter: 'The language used by me at the DACA meeting was tough, but this was not the language used.'

Haiti said it was shocked by Trump's reported remarks on Thursday and summoned the top US diplomat in the country, asking for an apology if the vulgar term had been used.

El Salvador's government sent the US a formal letter of protest that said the president had 'implicitly' accepted the use of 'harsh terms detrimental to the dignity of El Salvador and other countries'.

Botswana also said it had summoned the US ambassador to that country to 'express its displeasure' and had asked him whether Botswana 'is regarded as a "s***hole" country'.

Trump's comments are extremely offensive to South Africa, said Jessie Duarte, a senior official with the ruling African National Congress.

In Geneva, UN human rights spokesman Rupert Colville said: 'These are shocking and shameful comments from the president of the United States. There is no other word one can use but "racist".'

The reported language was the latest in a long string of anti-immigrant and anti-Muslim comments by Trump that have been condemned as racist. He also blamed 'both sides' after a white supremacist rally in August in Charlottesville, Virginia, turned violent and a woman protesting against the rally was killed.

Russell Moore, president of the Ethics and Religious Liberty Council of the Southern Baptist Convention, tweeted: 'The church of Jesus Christ is led by, among others, our brothers and sisters from Africa, Latin America, and the Caribbean. They are us.'

He later added, quoting from the New Testament book John 1:42-46: '"Can any good thing come out of Nazareth?" "Come and see."'

James Martin, a Catholic priest and editor of the Jesuit America Magazine also tweeted: '"Why are we having all these people from sh#*hole countries come here?" 1) They are our brothers and sisters in need. 2) They are often fleeing war, violence or famine. 3) There are children among them. 4) It's the right thing to do. 5) That's who we are.'

Additional reporting by Reuters.