President Donald Trump has recognized opposition leader Juan Guaido as Venezuela's interim president, sparking a standoff with Maduro who until now has retained the crucial backing of military leaders in Caracas.

Treasury Secretary Steven Mnuchin told reporters at the White House that new sanctions would prevent Maduro from diverting more resources from the crisis-wracked country until control in Caracas could be transferred to an interim or new democratically-elected government.

"The purpose of sanctions is to change behavior," Mnuchin said. "So when there is a recognition that the company is the property of, the rightful rulers, the rightful leaders, then indeed that money will be available to Guaido."

Ratcheting up the pressure, National Security Advisor John Bolton appealed directly to the military which has been essential to keeping Maduro in power since 2013.

"We also today call on the Venezuelan military and security forces to accept the peaceful, democratic and constitutional transfer of power," Bolton said.

"To a certain extent, this has begun," he said. "We've seen Venezuelan official and military personnel heeding this call," he added, citing the example of the country's military attache to Washington who broke ranks with Maduro at the weekend.

Asked whether Trump would consider getting the US military involved in Venezuela, Bolton replied: "The president has made it clear on this matter that all options are on the table."

Washington "is holding accountable those responsible for Venezuela's tragic decline," Mnuchin told reporters.

"We call on our allies and partners to join the United States in recognizing interim president Guaido and blocking Maduro from being able to access funds," he said.

Mnuchin added however that PDVSA's US-based subsidiary Citgo would be able to continue operations, as long as its earnings were deposited into a blocked account in the United States.

The latest sanctions on PDVSA, which has been a "vehicle for corruption... will help prevent further diverting of Venezuela's assets by Maduro and preserve these assets for the people of Venezuela," Mnuchin said.

"The path to sanctions relief for PDVSA is through the expeditious transfer of control to the interim president or a subsequent, democratically elected government."

The United States will issue temporary licenses to ensure US, Caribbean and European refineries that rely on Venezuelan crude can keep buying PDVSA oil, Mnuchin said, although he added that many had been taking steps to find other sources.