Iran has been experiencing technical problems with equipment in its uranium enrichment programme but it is unclear to what extent the Stuxnet computer worm may be to blame, Western diplomats said.

One senior diplomat said it was his understanding Iran had had to temporarily shut down some of its enrichment centrifuges due to power fluctuations, but he did not have details on how many or for how long.   

Security experts have said the release of Stuxnet could have been a state-backed attack possibly by Israel or another foe of Iran, on Iran's nuclear programme, which Tehran says is designed to produce electricity but which Western leaders suspect is a disguised effort to develop nuclear bombs.   

'I don't think you can necessarily blame Stuxnet entirely. There could be some other issues but clearly they have been having some real problems,' the diplomat told Reuters.   

Iran's envoy to the International Atomic Energy Agency (IAEA) was not immediately available for comment.   

Any delays in Iran's enrichment campaign could buy more time for efforts to find a diplomatic solution to its stand-off with six world powers over the nature of Iran's nuclear activities.

Iran denies any military aims but it has tentatively agreed to meet with a representative of the powers early next month, for the first time in over a year.

'Clearly there have been some technical difficulties they have been having with regard to centrifugues,' the Western diplomat said. 'They have been having some significant problems in terms of power fluctuations with the centrifuges ... They have had to shut some down.'    

Another Western diplomat also said Iran had been suffering problems with its centrifuges, without giving details.   

Security experts last week said new research showed definitively that Stuxnet was tailored to target the kind of equipment used in uranium enrichment, deepening suspicions its aim was to sabotage the Islamic Republic's nuclear activities.

Centrifuges are finely calibrated cylindrical devices that spin at supersonic speed to increase the fissile element in uranium so that it can serve as fuel for nuclear power plants or, if refined to a much higher degree, for atomic bombs.   

Iran's P-1 centrifuges, adapted from a smuggled 1970s European design, have been plagued by breakdowns since a rapid expansion of enrichment in 2007-08. In September, an IAEA report said the number of producing centrifuges had fallen to 3,772 from 3,936 a few months earlier. It did not give a reason. - Reuters