US President Donald Trump confirmed Sunday he had recently spoken with Venezuelan leader Nicolas Maduro amid soaring tensions between the two countries, while Caracas slammed what it called US preparations for an attack.

The United States is piling the pressure on Venezuela, with a major military buildup in the Caribbean, the designation of an alleged drug cartel run by Maduro as a terrorist group, and an ominous warning from Trump that Venezuelan airspace is “closed.”

Washington says the aim of the military deployment launched in September is to curb drug trafficking in the region, but Caracas insists regime change is the ultimate goal.

“I wouldn’t say it went well or badly. It was a phone call,” Trump told reporters Sunday aboard Air Force One.

The New York Times reported Friday that Trump and Maduro had discussed a possible meeting, while The Wall Street Journal said Saturday that the conversation also included conditions of amnesty if Maduro were to step down.

Republican Senator Markwayne Mullin said Sunday on CNN’s “State of the Union” talk show that the United States has offered Maduro the chance to leave his country for Russia or elsewhere.

The United States accuses Maduro, the political heir to Venezuela’s late leftist leader Hugo Chavez, of heading the “Cartel of the Suns” and has issued a $50 million reward for his capture.

But Venezuela and countries that support it insist no such organisation even exists.

Several Venezuela experts say what Washington calls the Cartel of the Suns refers to the corruption of senior officials by criminal gangs.

The United States also does not recognise Maduro as the legitimate winner of last year’s presidential election.

Though Trump has not publicly threatened to use force against Maduro, he said in recent days that efforts to halt Venezuelan drug trafficking “by land” would begin “very soon.”