The U.S. assets of four companies and one individual believed to be connected with the proliferation of weapons of mass destruction, or WMD, in Iran will be frozen as a result of Treasury Department action announced Friday.

Three of the companies -- the Chemical Industries and Development of Materials Group, Marine Industries Organization, and SAD Import Export Co. -- have ties either to Iran's Defense Industries Organization or the country’s Ministry of Defense and Armed Forces Logistics. The former was previously sanctioned by the U.S. in March 2007 for its involvement in the Iranian nuclear program; the latter was previously sanctioned by the U.S. in October of the same year for its WMD proliferation-related activities.

The fourth company, Doostan International Co., supports Iran's Aerospace Industries Organization, or AIO, the Treasury Department said. The AIO has been identified as a WMD proliferator by the U.S. For the same reason, it also was blacklisted by the European Union in 2007 and by Japan in 2009. It is reportedly controlled by the Islamic Revolutionary Guard.

The sanctioned individual is Mustafa Esbati, the director of the Marine Industries Organization, which secures weapons for the Iranian Navy and Revolutionary Guard.

The United Nations Security Council also froze the assets of the SAD Import Export Co. on Thursday. It is believed to be an arms supplier to Syrian President Bashar Assad's military. It is known to have previously shipped materials for rockets and missiles to Syria in 2010. The U.N. also sanctioned the cargo airline Yas Air.

The EU also announced Friday it is expanding its sanctions on Iran beyond the package passed in October, when it banned selling naval equipment and technology, as well as graphite and metals, to the Islamic Republic. The new sanctions will further restrict dealings with Iran's banks, natural-gas importers, and shippers, according to Agence France-Presse via Ahram Online.

Iran's nuclear program has fallen by the wayside in the minds of many in the West since the end of November, when Israel, which had previously been pushing the issue, became embroiled in the bombings on its terrority launched from the Gaza Strip.

Iran's economy has been hurting under the sanctions and will likely feel further pain with the new round: EU and U.S. sanctions have already cut Iran's oil exports by more than one-half this year, costing it more than $5 billion a month, Reuters reported.