Nicolás Maduro’s regime on Friday released six American citizens imprisoned in Venezuela after the strongman met in Caracas with President Donald Trump’s special envoy, Richard Grenell.

In a whirlwind trip, an envoy of President Donald Trump undid years of Biden administration diplomacy in Venezuela and started fresh with its President Nicolás Maduro, a shift that could have repercussions from migration to the oil market.

“He is there on a special mission,” said Mauricio Claver-Carone, the US state department special envoy for Latin America. “President Trump expects Nicolás Maduro to take back all of the Venezuelan criminals and gang members that have been exported to US, and to do so unequivocally and without condition.”