The Treasury said it would prevent so-called "U-turn" transfers to Iran as part of efforts "to expose Iranian banks' involvement in the Iranian regime's support of terrorist groups and nuclear and missile proliferation."
The action prevents fund transfers made on behalf of Iranian banks, persons or the Iranian government that are initiated offshore by non-Iranian banks or financial institutions and passed through the US financial system en route to other offshore, non-Iranian, non-US financial institutions, the Treasury said in a statement.
Prior to the ban, US financial institutions were authorized to process U-turn transfers for the direct or indirect benefit of some Iranian banks, persons Iran or the government.
The Treasury noted that it had previously designated five state-owned Iranian banks — Melli, Mellat, Sepah, Future Bank and the Export Development Bank of Iran — for "their role in Iran's weapons proliferation activities" as well as Bank Saderat "for providing support to terrorism."
"As a result of today's action, US financial institutions are no longer allowed to process these U-turn transfers" for any Iranian banks, state-owned or private, including the Central Bank of Iran, the Treasury said.
The move "protects our financial sector from the risks posed to the international financial system by Iran," the US State Department said in a statement.
"Last month, the Financial Action Task Force warned about the risks posed to the international financial system by the continuing deficiencies in Iran's anti-money laundering and terrorist financing regime, and in particular, highlighted Iran's lack of effort in addressing the risk of terrorist financing," it said.
The Treasury underscored that its move would not impair funds transfers by US financial institutions related to humanitarian aid or family remittances and travel-related remittances for Iranians.
Washington has steadily upped sanctions against Iranian businesses and financial institutions over the past several months in hopes of pressuring Tehran to pull back on its nuclear program — which the US says is aimed at developing nuclear weapons — and to halt its alleged support for groups Washington has labelled "terrorist," including Lebanon's Hezbollah and armed Palestinian groups.
