The African Group of UN ambassadors is "extremely appalled at, and strongly condemns the outrageous, racist and xenophobic remarks by the president of the United States of America as widely reported by the media," a statement said.

After an emergency session to weigh Trump's remarks, the group said it was "concerned at the continuing and growing trend from the US administration toward Africa and people of African descent to denigrate the continent and people of color."

While demanding a "retraction and an apology" from Trump, the 54 countries also thanked those Americans "from all walks of life who have condemned the remarks."

The resolution was passed unanimously after four hours of discussions.

"For once, we are all on the same page," an ambassador told AFP.

Related reading 'Made up': Trump denies 's***hole countries' slur as criticism mounts

The ambassadors did not consult their governments before issuing the resolution, he said, adding that some could now expect to receive phone calls from their capitals because of the text's strong tone.

Trump's comments were allegedly made on Thursday at a White House meeting with lawmakers on immigration reform.

After lawmakers raised the issue of protections for immigrants from African nations, Haiti and El Salvador, the president reportedly demanded to know why the United States should accept immigrants from "s***hole countries," rather than -- for instance -- wealthy and overwhelmingly white Norway.

He tweeted a convoluted denial Friday in an attempt to quell outrage both at home and abroad.

Earlier, the 55-nation African Union condemned the remarks, while Botswana and Senegal hauled in the US ambassador to complain.

The comment "truly flies in the face of accepted behavior and practice," said Ebba Kalondo, spokeswoman for AU chief Moussa Faki.

Western Sahara is not recognised as a sovereign state by the UN and thus not included in its African Group.

It is, however, part of the African Union, which Morocco left in 1984 over the body's recognition of the disputed territory's independence, before rejoining it last year.