The United States said yesterday it imposed sanctions on Iran's Defense Industries Organization (DIO) over its nuclear-related program.

The sanctions measure would require states to freeze the assets of the Iranian entity and not to have business dealings with it. The DIO is believed to be a company providing centrifuges to enrich uranium.

The U.S. measure is largely symbolic as Iran, a country branded by the United States as a "state sponsor of terrorism," has already been under U.S. sanctions.

The United States has accused Iran of trying to develop nuclear weapons under the cover of a civilian nuclear program. Iran has denied the charge and insisted its nuclear program is for peaceful purposes only.