It was also disclosed that power to an Iranian enrichment site was also cut off on an unknown date.
Explosives were used to cut the electricity power lines to Iran's Fordow underground enrichment plant last month in an apparent attempt to sabotage Tehran's atomic advances, its nuclear energy chief said on Monday.
It was believed to be the first time Iran has mentioned the incident, which atomic energy organization chief Fereydoun Abbasi-Davani said took place on Aug. 17.
He also told the annual member state gathering of the International Atomic Energy Agency (IAEA) that "the same act" had been carried out on power lines to Iran's main enrichment plant near the central town of Natanz, without giving a date.
Abbasi-Davani made clear his view that sabotage would not be successful in slowing Iran's nuclear program, which the West suspects is aimed at developing an atomic bomb capability but which Tehran says is purely peaceful.
He spoke a day after Israeli Prime Minister Benjamin Netanyahu warned that Iran would reach the brink of being able to build a nuclear bomb in six or seven months. [ID:nL5E8KG2P5]
Iran has often accused Israel and Tehran's Western enemies of being behind the assassination of Iranian nuclear scientists and of trying to damage its nuclear program in other ways, such as cyber attacks.
Abbasi-Davani said explosives had been used to cut power lines from the city of Qom to the Fordow underground uranium enrichment plant on Aug. 17. The next morning, he said, IAEA inspectors had asked for an unannounced visit to Fordow.