The Trump administration will allow a 30-day waiver of sanctions on Iranian oil at sea to expire later this week, two administration officials told Reuters on Tuesday, as the U.S. imposes a blockade on shipments from Iranian ports.

The waiver, which the Treasury Department issued on March 20, allowed some 140 million barrels of oil to reach global markets and helped relieve pressure on energy supply during the war on Iran, Treasury Secretary Scott Bessent said last month. The waiver is set to expire on April 19.

The move comes after lawmakers from both political parties criticized the administration for temporarily relaxing sanctions on Tehran and Moscow, while the U.S. and Israel are at war with Iran and as Moscow continues its war with Ukraine.

One of the U.S. officials said Washington has a range of authorities it can apply to institutions that buy Iranian oil, including secondary sanctions. "In addition, with the snapback of U.N. sanctions on Iran, and its history of trying to hide behind seemingly legitimate activity to conduct its illicit conduct, any activity with Tehran could trigger additional sanctions," the source said.