The Treasury Department statement stopped short of announcing a freeze on Venezuela's U.S. assets and accounts, however.

On Wednesday, Washington recognised National Assembly chief Guaido as Venezuela's interim president.

"The United States will use its economic and diplomatic tools to ensure that commercial transactions by the Venezuelan government, including those involving its state-owned enterprises and international reserves, are consistent with this recognition," the U.S. Treasury said in a statement.

The announcement came as Washington intensified its push to drive socialist Maduro from power. Maduro began a second term earlier this month after winning disputed elections last year, and is still supported by the Venezuelan military.

Maduro said earlier he would defend Citgo, the U.S. refining subsidiary of Venezuelan state oil company PDVSA, amid moves by Guaido to divert its revenues, sources close to the talks told Reuters.

(Reporting by Lesley Wroughton, Editing by Rosalba O'Brien)