Washington  - The US government on Tuesday placed sanctions on an additional five Iranian entities accused of supporting the Islamic state's nuclear and missile activities.

The US Treasury Department said the entities served as front organizations to assist in the country's development of nuclear technology and ballistic missiles.

"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 Department's undersecretary for terrorism and financial intelligence.

The Treasury Department said three of the entities are controlled by Iran's Atomic Energy Organization. They are: The Nuclear Research Centre for Agriculture and Medicine at Karaj, The Esfahan Nuclear Fuel Research and Production Centre and a laboratory called Jabbar Ihn Hayan.

The other two, the Safety Equipment Procurement Co and and Jaza Industrial Co, are fronts for Iran's ballistic missile programmes, the Treasury Department said.

Iran rejects Western suspicions that it is using a civilian nuclear programme to develop the capability to build atomic weapons.

The UN Security Council has enacted three round of limited sanctions on Iran for its refusal to halt uranium enrichment. (dpa)