The Treasury Department added five Iranian companies to its financial blacklist, including two banks, an insurance company, a freight forwarder and the state-owned shipper, the Islamic Republic of Iran Shipping Lines. The sanctions bar the firms, all linked to Iran's Revolutionary Guard Corps, from the U.S. financial system and freeze any assets they may have in US jurisdictions.

“Both the IRGC and IRISL are major institutional participants in Iran's illicit conduct and in its attempts to evade sanctions,” said Under Secretary of Treasury for Terrorism and Financial Intelligence Stuart Levey. “We will therefore continue to target and expose their networks.” The sanctions target the Moallem Insurance Company for providing marine insurance to IRISL vessels, and the Ansar Bank and Mehr Bank for providing financial services to the IRGC.

Also affected is Bonyad Taavon Sepah, a quasi-governmental financial services firm that handles investments for the Revolutionary Guard. Bonyad Taavon Sepah's Executive Director Parviz Fattah was also blacklisted.

The forwarder, Liner Transport Kish, was added to the blacklist for providing material support, including weapons to Hezbollah on behalf of the Revolutionary Guard.

In addition, Treasury identified an Iranian energy concern, Pars Oil and Gas Company, as being owned or controlled by the government, hitting it with sanctions under new US legislation aimed at choking off financing for illicit activity.

The Revolutionary Guard and the state-run shipping line are subject to existing US sanctions designed to compel the country to make public its nuclear intentions, stop the proliferation of weapons of mass destruction and ballistic missiles and end support for terrorist groups.

American officials say the sanctions are having an effect and have forced the Guard Corp and shipping line to set up front companies and take other steps to evade the penalties.