Abdolfattah Soltani was arrested Saturday while he holding a sit-in at a Tehran bar building to protest against a search of his house and an arrest warrant issued against him. Until now it was not known why he was arrested.

"Based on a comprehensive report by the intelligence ministry, he has talked about confidential issues of nuclear spies inside and outside the country," judiciary spokesman Jamal Karimi Rad told the student agency ISNA.

Soltani, a member of Ebadi's centre to defend human rights, represents Iran's highest profile political prisoner, journalist Akbar Ganji, the family of murdered Iranian-Canadian photographer, Zahra Kazemi, and also suspects in the nuclear espionage case.

Iran announced in 2004 that it had arrested a dozen people on suspicion of spying on Iran's nuclear programme for US and Israeli intelligence services.

Two of them are due to be tried on August 2 and 20, Karimi Rad told AFP. Another has already been sentenced, he said without specifying the details. That case is currently pending for appeal, Karimi Rad said.

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