Iran has insisted that its nuclear project was not affected by a mystery computer virus attack.
It said the worm known as Stuxnet had not caused any damage but accused the West of being behind it.
Vice President Ali Akbar Salehi revealed the virus attempt a day after diplomatic sources said that Iran’s nuclear programme had suffered a recent setback, with major technical problems forcing the temporary shutdown of thousands of centrifuges enriching uranium.
Mr Salehi said details about the virus became known only after Iran’s “enemies failed to achieve their goals.”
Iran earlier confirmed that Stuxnet infected several personal laptops belonging to employees at the Bushehr nuclear power plant but that plant systems were not affected.
The West has accused Iran of using the nuclear programme to develop an atomic weapon. Tehran dismisses the claim, saying it is for peaceful purposes only.
The UN nuclear watchdog, the International Atomic Energy Agency, said the Iranian uranium enrichment capacity has stagnated after initial rapid growth.
Tehran has taken hundreds of centrifuges off line over the past 18 months, prompting speculation of technical problems.
At the Natanz enrichment facility the number of operating centrifuges declined from 4,920 in May 2009 to 3,772 in September 2010, the IAEA said.
Suspicions have focused on the Stuxnet worm which experts last week identified as being designed to destroy centrifuges by sending them spinning out of control.