A group close to the Iranian opposition in exile said Thursday it has located an industrial site near Tehran that produces components for centrifuges used to enrich uranium.

The Taba site has been in operation for four and a half years, Alireza Jafarzadeh said at a news conference in Washington, citing information gathered by the People's Mujahedeen of Iran (PMOI) opposition group.

Taba, which in Persian stands for Iranian Cutting Tools Factory, produces "aluminium casing, magnets, molecular pumps, composite tubes, centrifuge bases," he said.

Several aerial photographs of industrial installations were presented at the news conference. The site was said to be located in Karaj in Tehran's western suburbs.

"This is another indication that Tehran, unlike what it says, is not transparent, (does not intend) to be cooperative with the international community, is not pursuing a peaceful nuclear energy program, because otherwise there's no need for any of these things, no need to hide the program since 2002," Jafarzadeh said.

He said there was also another factory for making centrifuge components in Sahfizadeh, near Qazvin, 130 kilometers (80 miles) west of Tehran, but provided few details.

He said Iran's capacity to build centrifuges, and the number of them in operation in the country, was a critical question for determining the true intentions and goals of the Iranian nuclear program.

The Iranian opposition in exile has passed detailed information on its findings to the US administration and the International Atomic Energy Agency, he said.

The major powers accuse Iran of secretly seeking to acquire nuclear weapons under the cover of a civilian nuclear program, a charge Tehran denies.

The Iranian nuclear program has been condemned in six UN Security Council resolutions, which have included four sets economic and political sanctions. The United States and other countries have adopted their own sanctions as well.