The US Treasury announced the new measures as part of a global effort to step up pressure on Iran to halt its disputed nuclear activities.

"Iran's nuclear and missile firms hide behind an array of agents that transact business on their behalf," said Stuart Levey, the Treasury under secretary for terrorism and financial intelligence.

"As long as Iran continues to engage in such deceptive practices, companies and banks must exercise extraordinary vigilance to avoid participating in illicit transactions."

The Treasury-named individuals include Dawood Agha-Jani, Moshen Hojati, Mehrdada Akhlaghi Ketabachi, and Naser Maleki and the entities designated include Shahid Sattari Industries, Seventh of Tir, Ammunition and Metallurgy Industries Group, and Parchin Chemical Industries.

This action was taken on the basis of a US executive order aimed at freezing the assets of proliferators of weapons of mass destruction and their supporters, and at isolating them from the US financial and commercial systems.

In June 2005, Washington designated the Atomic Energy Organization of Iran (AEOI), Iran's Aerospace Industries Organization (AIO), the Shahid Bakeri Industrial Group (SBIG), and the Shahid Hemmat Industrial Group (SHIG) as entities of proliferation concern.

According to Treasury, the AEOI, which reports directly to the Iranian president, is the main organization for research and development activities in the field of nuclear technology, including Iran's centrifuge enrichment program.

Those in the latest sanctions have links to one or more of the entities already designated for sanctions.

The announcement came after the European Union added 20 individuals and 15 organizations to the EU's visa-ban and assets-freeze lists.

Washington has been waiting for Europe to take such measures for months, and the matter became a theme of US President George W. Bush's recent European tour.

Tehran insists it wants atomic energy only for a growing population whose fossil fuels will eventually run out.

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