The head of Iran's atomic agency says blasts cut power lines to the country's underground nuclear facility at Fordo last month.
"On ... August 17 2012, the electric power lines from the city of Qom to the Fordo complex ... were cut using explosives," Fereydoon Abbasi Davani told the 155-nation International Atomic Energy Agency (IAEA) gathering in a speech.
Davani did not accuse anyone in particular, but in the past Iran has blamed Israel and the United States for the assassinations of its nuclear scientists and computer viruses targeting its atomic facilities.
He also suggested that the IAEA requested a visit the next day in order to assess the damage.
"During the early hours of next morning an agency inspector requested to conduct an unannounced inspection. Does this visit have any connection to that detonation?" Abbasi said through an interpreter.
"Who other than the IAEA inspectors can have access to the complex in such a short term to report and record failures? It should be reminded that the same act had been performed on the power lines to the Natanz facilities."
Fordo is a key site in Iran's nuclear programme, dug deep into a mountain to protect it against air strikes and enriching uranium to purities of 20%, a short step from the 90% needed for a nuclear weapon.
Iran says its nuclear programme is peaceful and that uranium enrichment is for power generation and medical purposes.
Many in the international community suspect otherwise and the UN Security Council has passed six resolutions calling for a suspension of enrichment. Israel and the US have also refused to rule out military action.
Abbasi, due to hold talks later on Monday in Vienna with IAEA chief Yukiya Amano, said however that sabotage attempts against Iran's nuclear activities have failed and would continue to fail – as would any air strikes.
"The plotters of attacks against Iranian nuclear facilities have realised, through the IAEA's published reports, that they have not gained any success in this regard," he said.
Abbasi said that experts from Iran were now able to anticipate unwanted events "and ward off threats by targeting virtual packages of cyber-attacks, industrial sabotage and use of explosives".
"They have also devised certain ways through which nuclear facilities remain intact under missile attacks and air raids," Abbasi added.
He also blamed the IAEA for the failure of a string of meetings this year aimed at clarifying the agency's suspicions that prior to 2003, and possibly since, Iran had a structured programme of activities it said were "relevant to the development of a nuclear explosive device".
"The IAEA's approach has been such that negotiations fail ... One can create a major obstacle along the way and then say that negotiations to overcome that obstacle have been [in] vain," Abbasi said.
The latest meeting between the IAEA and Iran on August 24 ended without agreement. Other talks took place in May and in June. Amano also visited Tehran in May, as did a team led by chief inspector Herman Nackaerts at the start of the year, returning however with no deal.
Parallel higher-level diplomatic meetings between Iran and the P5+1 – Britain, China, France, Russia, the United States and Germany – took place in Istanbul, Baghdad and Moscow earlier this year but were downgraded to working-group level.
But EU foreign policy chief Catherine Ashton, P5+1 chief negotiator, will meet her counterpart from Iran Saeed Jalili in Istanbul on Tuesday, her office said on Monday.
It would be their first face-to-face meeting since the Moscow talks in June, although the two spoke by telephone in early August. Earlier this month EU foreign ministers discussed imposing more sanctions on Tehran. – AFP