Nigeria’s government on Monday summoned the United States ambassador to explain reported remarks by U.S. President Donald Trump that some immigrants from Africa and Haiti come from “shithole” countries, Foreign Minister Geoffrey Onyeama said.

He was responding to a text message from Reuters in which he confirmed that Ambassador Stuart Symington had been summoned. He gave no more details.

Trump reportedly made the remarks at a private meeting with lawmakers on immigration on Thursday. A U.S. senator who attended the gathering said the president used “vile, vulgar” language, including repeatedly using the word “shithole” when speaking about African countries.

The U.S. president on Friday denied using such derogatory language. But he has been widely condemned in many African countries and by international rights organizations. African Union countries demanded an apology on Friday.