Dec 1 (Reuters) - Venezuela's President Nicolas Maduro is running out of options to step down and leave his country under U.S.-guaranteed safe passage, following a short call with U.S. President Donald Trump last month where Trump refused a series of requests from the Venezuelan leader, according to four sources briefed on the call.

President Trump scheduled a meeting with top generals and Cabinet officials on the matter at the White House on Monday evening, debating target options now available with the deployment of more than a dozen warships to the Caribbean Sea.

The White House will hold a meeting on Venezuela as President Donald Trump confirmed speaking with President Nicolás Maduro amid escalating tensions.

The US says it is fighting drugs smuggling, but Venezuela says Donald Trump's aim is to topple President Nicolás Maduro.

President Donald Trump announced Saturday that the airspace above and surrounding Venezuela should be considered "closed in its entirety."

Venezuela’s government said it “forcefully rejects” Trump’s claim about closing the airspace and that it was a “colonial threat” intended to undermine the country’s “territorial integrity, aeronautical security and full sovereignty.”

President Trump is considering next steps for operations in Venezuela, as lawmakers intensify their scrutiny of the Pentagon's deadly strikes on alleged drug boats.