TEHRAN, Iran - Iran said Tuesday it has arrested a man on suspicion of selling nuclear secrets to an exiled Iranian opposition group, state radio reported.

The report didn't identify the suspected spy, but said he had been working at the Iranian Parliament's Research Center, an organization that advises lawmakers on foreign and strategic issues.

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"The man transferred classified information, including a bulletin on nuclear activities, to the hypocrites," state radio said, referring to the People's Mujahedeen of Iran.

The Paris-based group, regarded as a terrorist organization by the United States, has frequently made accusations about Iran's nuclear activities, reporting on what it says is secret information received from insiders in Iran.

In 2002, the group disclosed the existence of two previously secret nuclear facilities, a pilot uranium enrichment plant at Natanz and a research reactor being built in the city of Arak, which turned out to house Iran's uranium enrichment program and a hard-water reactor project. Other claims by the group have not been substantiated.

Iran said in 2004 that it had arrested 10 military officers, nuclear workers and others on charges of revealing its nuclear secrets to Israeli and US intelligence agencies.

But the government said the information passed to the United States and Israel was "without value."

Ahmed Tavakoli, a leading lawmaker, confirmed state radio's report of the arrest of the alleged spy.

"This person has been working in Parliament's Research Center since 2001," Tavakoli told the semiofficial Fars news agency Tuesday. "He was arrested by the Intelligence Ministry."

Tavakoli told Fars that the arrested man will stand trial but gave no date.

The People's Mujahedeen participated in the 1979 ouster of the former shah of Iran, Mohammed Reza Pahlavi. But it fell out with the clerical government and launched a campaign of assassinations and bombings.

For years it fought Iran's Islamic rulers from Iraq with the backing of Saddam Hussein's regime.

During the US-led invasion of Iraq, the US military briefly bombed People's Mujahedeen camps until the group capitulated and agreed to disarm.