Washington DC - President Donald Trump said Friday that Colombian President Gustavo Petro, a leftist his administration long belittled, will visit the White House next month as he voiced optimism for ties.

Trump just days ago had threatened Petro in the wake of the US attack that removed Venezuela's leader, but Trump appeared to have a change of heart after the two spoke by telephone on Wednesday.

"I look forward to having a meeting with Gustavo Petro, the President of Colombia, in the White House, during the first week of February," Trump wrote on his Truth Social platform.

"I am sure it will work out very well for Colombia, and the USA, but, cocaine and other drugs must be STOPPED from coming into the United States," Trump wrote.

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Petro, the close US ally's first left-wing president, was slapped with US sanctions in October over allegations of not cooperating with Washington against drugs.

Petro, who leaves office this year and cannot seek re-election, has been among the most vocal US leaders in criticizing Trump, who has responded ferociously.

Soon after Trump returned to the White House, his administration briefly suspended issuing visas to Colombians after Petro resisted US flights of deported migrants.

Secretary of State Marco Rubio, a sworn critic of Latin America's leftists, has made clear his distaste for Petro, publicly calling him a "lunatic."

Trump on Saturday said that Petro should "watch his a**" after the Colombian leader criticized the US operation that snatched Venezuela's leader Nicolás Maduro.

The abrupt change in approach mirrors Trump's reconciliation after initial tensions with Brazil's left-wing president, Luiz Inacio Lula da Silva, after Lula greeted Trump when they crossed paths at the United Nations in September.