The Trump administration is imposing a ban on travel to the United States by members of Venezuela’s government-controlled constituent assembly, a senior US official said on Thursday.

The US has claimed the constituent assembly, headed by President Nicolas Maduro, is illegitimate, pledging its support to opposition leader Juan Guaido.

Elliott Abrams, Washington’s special envoy on Venezuela, said the time for dialogue with Maduro “has long passed”, except to negotiate his departure, and reinforced US backing for Guaido, the self-proclaimed interim president who has earned recognition from the US and a number of other countries.

News of the US-imposed travel restrictions came as European and Latin American leaders called on Thursday for a dialogue between the Venezuelan government and the opposition, warning against rash intervention in the country.

Russia and China continue to back Maduro’s government and have warned the US and others not to intervene.

Maduro and his supporters say the US is attempting to carry out a coup in Venezuela. In 2002, the opposition attempted to overthrow then-President late Hugo Chavez in a failed coup attempt.

Also on Thursday, trucks carrying humanitarian aid for the crisis-struck civilians lined up near the Venezuelan-Colombian border.

It was unclear if Maduro’s government would allow aid into the country. The Venezuelan military barricaded a bridge between the two countries with a tanker and two cargo trailers in an apparent attempt to block the aid.