The United States and Israel are behind the computer worm Stuxnet designed to hurt Iran's controversial nuclear programme, state news agency IRNA reported Saturday quoting a military officer.

"Investigations and studies show that the source of Stuxnet originates from America and the Zionist regime," the commander of the Iranian civil defence organisation, Gholam Reza Jalali, said.

Jalali was the first Iranian official to accuse Tehran's two arch-foes over the Stuxnet virus. German computer experts and some Western media reports had indicated that the United States and Israel were behind it.

Stuxnet was publically identified last June and it reportedly mutated and wreaked havoc on computerised industrial equipment in Iran in the following months.

The worm was reportedly targeting Bushehr nuclear power plant, where several technical problems have been blamed for delays in getting the facility fully operational.

Jalali said once the worm mounts on a system, it begins to gather information and then sends reports from the infected machines to designated Internet addresses.

"After following up the reports that were sent, it became clear that the final destinations (of these reports) were the Zionist regime and the American state of Texas," he was quoted as saying by IRNA.

In March, a German computer security expert Ralph Langer said he believes the United States and Israel's Mossad had unleashed the Stuxnet worm on Iran's nuclear programme.

But it was the New York Times which reported first in January that US and Israeli intelligence services collaborated to develop the computer worm to sabotage Iran's efforts to make a nuclear bomb.

In November 2010, Iranian President Mahmoud Ahmadinejad admitted that uranium enrichment -- the most controversial part of Tehran's nuclear programme - had suffered problems caused by the malware but added the issues had been resolved.

Iran's nuclear ambitions are at the heart of a conflict between Tehran and the West, which accuse the Islamic republic of seeking to develop a weapons capability under the cover of a civilian nuclear drive.

Tehran vehemently denies the charges.