CARACAS—The U.S. is evaluating whether to impose tougher sanctions against Venezuela’s military and vital oil industry, a senior White House official said Monday, as it seeks to ratchet up pressure on authoritarian leader Nicolás Maduro to hold free and fair elections.

The Trump administration is considering a range of measures including curtailing the flow of Venezuelan oil to the U.S., the official said, in what could be the harshest blow to the country's money supply. No final decision has been made.