The Treasury said the entities, designated as proliferators of weapons of mass destruction, are controlled by or act on behalf of previously blacklisted Iranian entities responsible for uranium enrichment, nuclear development work and ballistic missile programs.
Added to the Treasury's sanctions list were the Nuclear Research Center for Agriculture and Medicine at Karaj, the Eshfahan Nuclear Fuel Research and Production Center, Jabber Ibn Hayan, Safety Equipment Procurement Co and Joza Industrial Co. The move bans Americans from doing business with them and freezes any assets they may have under U.S. jurisdiction.
Western powers fear Tehran wants to build an atomic bomb. Iran says it is only seeking to master nuclear technology to generate electricity.
"These five nuclear and missile entities have been used by Iran to hide its illicit conduct and further its dangerous nuclear ambitions," said Stuart Levey, the Treasury's undersecretary for terrorism and financial intelligence.
"Responsible financial institutions and businesses worldwide are taking steps to avoid doing business with Iranian nuclear and missile entities, as well as with the front companies and cut-outs the Iranian regime uses to disguise its activities," Levey said in a statement.
The new designations come as the United States, Britain, France and Germany are considering imposing broader economic sanctions beyond the steps likely to be considered in the next round of United Nations sanctions.
A senior British official said on Friday areas under consideration may include liquefied natural gas, investment in oil and gas, imported refined products, reinsurance and other financial areas.
The Treasury has banned dealings with several Iranian state banks, including its largest, Bank Melli. Treasury officials have criticized Iran's central bank for helping blacklisted entities try to skirt international sanctions, but so far have not attempted to ban dealings with it.
The Treasury said the Nuclear Research Center for Agriculture and Medicine, the Esfahan Nuclear Fuel Research and Production Center and Jabber Ibn Hall were acting on behalf of the Atomic Energy Organization of Iran, an entity sanctioned by the U.N. for its role in Iran's nuclear program.
The other two firms had acted on behalf of Iranian entities previously sanctioned for their work in acquiring ballistic missile technology and development work on the Shahab series of medium-range missiles.
(Reporting by David Lawder; Editing by Alan Elsner)
