The United States has issued a new round of sanctions against Iran, seeking to disrupt oil exports by going after a global network of companies owned by a single Greek shipper.

In a statement published by the US Treasury Department on Thursday, the government announced sanctions on companies and vessels owned by Antonios Margaritis. The sanctions follow several other rounds aimed at making it more difficult for Tehran to sell oil abroad.

“Margaritis has leveraged his decades of experience in the shipping industry to illicitly facilitate the transportation and sale of Iranian petroleum,” the statement notes. “Several other vessels and operators are also being designated today for their role facilitating Iranian oil exports, which generates revenue that contributes to Iran’s advanced weapons programs.”

Nine companies based in Greece, Hong Kong, the Marshall Islands and the United Arab Emirates were sanctioned, along with 12 vessels – some of which carry flags of convenience from other nations.

Among those sanctioned was the Marshall Islands-based Changbai Glory Shipping Limited, the owner of a Liberian-flagged ship that since March 2025 alone has transported more than four million barrels of Iranian oil to China.

China is the top international buyer of Iran’s oil. The US has sought to penalise Iran’s energy sector since a Washington-backed ceasefire between Israel and Iran came into effect in June.