President Donald Trump's administration has continued to increase punitive measures against Venezuela since January, when Washington -- along with 50 other countries -- recognized opposition leader Juan Guido as the crisis-ridden country's interim leader.

Russia, North Korea and Cuba continue to support Maduro.

"The pressure will continue, we'll have more sanctions tomorrow," said Elliott Abrams, the White House's pointman on Venezuela.

He added he thinks the pressure has had a "fairly dramatic" effect on Maduro's regime, though the leader has yet to leave power.

Abrams did not specify what the sanctions, which will be announced Thursday, will include.

During a conference organised by the Washington-based think tank The Foundation for Defense of Democracies, Abrams said Washington would also increase pressure on Cuba for its actions in Venezuela supporting Maduro, the same reason for the new sanctions against Russia.

"On Russia, we are still thinking about what sanctions to apply, individual or sectorial," Abrams said.

"They are not giving any more money to Venezuela. They are taking their money out," he said.

"Nevertheless, they are helping merchandise their oil to some extent, and that is something we are thinking about."

Washington, which has imposed an oil embargo on Caracas to undermine Maduro's regime, has repeatedly called on Moscow to withdraw its support for the Venezuelan leader.

Russia has rejected the request, accusing the US of wanting to lead a coup in defiance of international law.