President Nicolas Maduro has met with an envoy sent by US President Donald Trump, despite the United States' refusal to recognize Maduro as the legitimate president of Venezuela.

Maduro and Trump's special envoy, Ric Grenell, held talks on Friday in the south American country.

The Venezuelan government said the topics included migration, and that the need to change the direction of bilateral relations was confirmed.

The White House press secretary said on Friday that Grenell was dispatched to discuss repatriation of Venezuelan gang members detained in the US and the return of US detainees in Venezuela.

Later in the day, Grenell said on social media, "We are wheels up and headed home with these 6 American citizens."

The United States has not recognized Maduro's legitimacy, saying that opposition candidate Edmundo Gonzalez was the winner of last year's presidential election.

Trump dismissed concerns that the dispatch of his envoy could lend legitimacy to the Maduro administration, saying, "We want to do something with Venezuela." He told reporters on Friday that Maduro has treated Venezuelan people very badly and added, "Now we want to see what we can do to get people back in their homeland safe and free."