Asked in an interview with CBS's "Face the Nation" what could lead the United States to use military force in the crisis-wracked country, the president declined to give a specific answer.

"But certainly it's something that's on the -- it's an option," he said.

The United States recognized Venezuelan opposition leader Juan Guaido as interim president on January 23, and is leading an international campaign to drive Maduro from office.

Guaido says the constitution entitles him to serve as interim head of state because Maduro's re-election last May was invalid, his strongest opponents having been barred from running.

Four major European nations -- Britain, France, Germany and Spain -- have said they will likewise recognize Guaido's opponent unless Maduro calls new presidential elections by midnight on Sunday.

Trump has repeatedly warned "all options are on the table" in Venezuela, as his administration ramps up the pressure on Maduro through economic sanctions and appeals to the country's armed forces to switch allegiances.

Under Maduro's stewardship, oil-dependent Venezuela has lurched into an economic crisis that has left it suffering from hyperinflation and shortages of food and medicine.

Maduro refuses to let aid into Venezuela, claiming it would precede a US-led military intervention.