The Trump administration is considering imposing some U.S. sanctions on Venezuela’s vital oil sector in response to Sunday’s election of a constitutional super-body that Washington has already denounced as a “sham” vote, U.S. officials said. The measures, which could be announced as early as Monday, are not expected to include a ban on Venezuelan oil shipments to the United States — one of the harshest options — but could block sale of lighter U.S. crude that Venezuela mixes with its heavy crude and then exports, the officials told Reuters. While no final decisions have been made, the officials, who spoke on condition of anonymity, said the United States could also sanction further senior Venezuelan officials. But the timing of such an announcement remained uncertain, the sources said.