Ghana's President Nana Akufo-Addo today said US President Donald Trump's reported description of African nations as "sh**hole countries" was unacceptable, while his predecessor branded the US head of state a racist.
On Thursday, Mr Trump reportedly demanded to know why the US should accept immigrants from "sh**hole countries", after lawmakers raised the issue of protections for immigrants from African nations, Haiti and El Salvador.
He has since denied using the reported language.
President Akufo-Addo tweeted that Mr Trump's reported language was "extremely unfortunate", adding: "We are certainly not 'a sh**hole country'."
"We will not accept such insults, even from a leader of a friendly country, no matter how powerful."
Ghana is widely seen as a stable, peaceful country in an often turbulent region, and has close ties to the United States.
Mr Akufo-Addo's comments follow a strongly worded African Union statement last night and a demand from African ambassadors at the United Nations for a retraction and an apology.
The group of UN diplomats said it was "extremely appalled at, and strongly condemns the outrageous, racist and xenophobic remarks".
Ghana's former president John Dramani Mahama, whom Mr Akufo-Addo defeated in elections just a month after Mr Trump's own win at the polls, on Twitter asked: "Isn't Trump demonstrating that he's nothing but a racist and pursuing a policy of 'Make America White Again'?"
He also highlighted the contrast between Mr Trump's praise for Africa last year when he met leaders from the continent on the sidelines of the UN General Assembly.
"Sh**hole? Thought they said he was so impressed with us just last September?" Mr Mahama tweeted under a mocked-up photograph of Mr Trump being shown a map of Africa in which all the countries were labelled "Nambia".
Mr Trump was widely derided last year after twice referring to Namibia as 'Nambia' at the September meeting.
Namibia added its voice to the chorus of complaints, saying Mr Trump's language had "no place in diplomatic discourse" and was "contrary to the norms of civility and human progress".
"The Africa we know and live in is one that is recovering economically and rising," it added.
"The USA we know is one that was built with blood and sweat of African slaves and immigrants from all over."
Mr Trump tweeted a convoluted denial yesterday in an attempt to quell outrage both at home and abroad.
Never said anything derogatory about Haitians other than Haiti is, obviously, a very poor and troubled country. Never said "take them out." Made up by Dems. I have a wonderful relationship with Haitians. Probably should record future meetings - unfortunately, no trust!— Donald J. Trump (@realDonaldTrump) January 12, 2018
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.