The United States has unveiled a new round of sanctions targeting Iran’s oil sector, only hours after American and Iranian officials concluded a day of indirect talks in Oman over Tehran’s nuclear programme.

State Department spokesman Tommy Pigott said Washington is intensifying efforts to choke off the revenue Iran earns from oil and petrochemical exports, arguing that those funds are used to finance regional militias, missile programmes and domestic repression. He framed the move as part of a broader campaign to counter what US officials describe as Iran’s destabilizing activities across the Middle East, from support for armed groups in Lebanon, Iraq and Yemen to backing for Syria’s government.

The latest measures focus on the maritime network that moves Iranian crude and refined products in defiance of existing restrictions. According to the State Department, the United States is blocking transactions involving 14 vessels accused of transporting Iranian oil, some of them sailing under Turkish, Indian and Emirati flags. Sanctions were also imposed on 15 companies and two individuals alleged to be involved in arranging shipments, concealing cargo origins or facilitating payments through complex front operations.

US officials say the goal is to make it riskier and more expensive for Iran to move its oil, by pressuring shipowners, insurers, traders and banks that might otherwise handle the cargoes. The measures build on years of US efforts to deter third countries from buying Iranian crude, a policy that has periodically squeezed Iran’s export volumes and foreign currency earnings.

The announcement came on the heels of indirect talks in Oman, where Iran’s foreign minister and senior US envoys used Omani mediators to exchange proposals on nuclear and regional issues. Iranian officials described the atmosphere as positive, but the new sanctions underscored how far the two sides remain from any comprehensive understanding.

The diplomatic contacts follow a period of acute strain. Iran’s leadership has faced international condemnation for its violent response to mass protests at home, while the United States has bolstered its military posture around the Gulf, warning that it will respond to attacks on its forces or partners. The fresh sanctions signal that Washington intends to keep tightening economic pressure even as it tests limited diplomatic channels.