The US on Friday imposed sanctions on Turkey's Golden Global Bank and two of its subsidiaries, accusing the financial institution of facilitating tens of millions of dollars in transactions for Iran's Islamic Revolutionary Guard Corps.
The US Department of the Treasury said the bank had provided correspondent banking services to Iranian financial institutions, enabling transactions through accounts controlled by the IRGC and its proxies.
Treasury said the bank was also established to help Iran transfer oil revenues from China to Turkey, where the funds could be converted into cash and gold through money exchangers.
The new sanctions cover Golden Global Yatirim Bankasi Anonim Sirketi and its subsidiaries Golden Global Varlik Kiralama Anonim Sirketi and Golden Global Portfoy Yonetimi Anonim Sirketi.
"Financial institutions continue to find out the hard way that we are serious about Operation Economic Outcast," Treasury Secretary Scott Bessent said in a statement.
The latest measures underscore the US's effort to tighten pressure on Iran's ability to move money internationally as Washington targets banks and other entities it says facilitate sanctions evasion.
Treasury said Iran, already subject to broad US sanctions, relies on multi-jurisdictional shadow banking networks to generate revenue and transfer funds abroad.
The US Department of the Treasury said the action was part of "Operation Economic Outcast," a campaign to target the Iranian government's revenue sources and financial networks used to evade sanctions.
The department said it was working with the European Union, Britain, Gulf partners and other US government agencies to target Iran's illicit revenue sources and sanctions-evasion networks.
Elsewhere, Secretary Scott Bessent also said that since the US reinstated its blockade, no Iranian crude cargoes had successfully transited the Strait of Hormuz to China, leaving oil stranded aboard vessels inside the waterway and limiting Tehran's ability to replenish inventories.
Iran's ability to export crude has been increasingly constrained by the disruption, Treasury said, describing the combination of stranded oil, limited storage capacity and declining revenues as a growing pressure point for Tehran.