The US government on Thursday took aim at Iran's "shadow fleet" of oil tankers, imposing sanctions on 29 vessels.
The vessels and companies have shipped hundreds of millions of dollars of the products through deceptive shipping practices, the US Treasury said.
State Department spokesman Tommy Pigott said the sanctions would limit Iran’s ability to export petroleum and petroleum products through "obscure and fraudulent mechanisms".
The shadow fleet refers to ships that carry oil that is under sanctions. They are typically old, their ownership opaque and they sail without the top-tier insurance needed to meet international standards for oil majors and many ports.
Treasury will "continue to deprive the regime of the petroleum revenue it uses to fund its military and weapons programmes", John Hurley, the department's undersecretary for terrorism and financial intelligence, said in a statement.
Iran's mission to the UN did not immediately respond to a request for comment.
The US says it imposes sanctions on Iran over Tehran's nuclear programme and its support of militant proxies across the Middle East. Iran says its nuclear work is for civil purposes.
