The United States on Monday imposed sanctions on a state-owned oil firm in Venezuela, said the White House.

The sanctions on Petroleos de Venezuela, S.A., or known as PDVSA, will block seven billion U.S. dollars in assets and could result in 11 billion dollars in lost sales over the next year, U.S. National Security Adviser John Bolton told reporters at a White House daily briefing.

Washington's new designation came days after it recognized the opposition leader Juan Guaido as Venezuela's interim president, denouncing incumbent President Nicolas Maduro who won the elections last year with over two thirds of the votes.

Bolton warned Maduro that he would be held responsible for the safety of U.S. diplomatic personnel in Venezuela as well as Guaido and other opposition figures.

He also did not appear to rule out U.S. military intervention, though such action is widely considered to be unlikely.

"The president has made it very clear on this matter that all options are on the table," Bolton said.

Maduro says the United States is promoting a coup against him and promised to stay in office.

He also slammed Guaido's move to declare himself the interim president as unconstitutional.