Russia has for the first time laid the blame for the Stuxnet worm at the door of the US and Israel, describing it as "the only proven case of actual cyber-warfare."
In translated comments reported by the AFP agency, foreign ministry security department chief Ilya Rogachyov was blunt about the origins of a piece of malware that has mystified experts since first appearing in June 2010.
"Experts believe that traces of this lead back to the actions of Israel and the United States," he said. "We are seeing attempts of cyberspace being used by some states to act against others [and] of it being used for political-military purposes," he added.
After branding Stuxnet as an act of cyberwarfare, Rogachyov continued. "The only case in which experts believe the actions of states have been proven in this area [...] is the Stuxnet system that was launched in 2010 against the centrifuge control system used to enrich uranium in Iran."
The timing of the comments will be seen as significant in a week when Iran said it had asked Russia to help it build a second nuclear facility to complement the Bushehr plant that has caused so much tension with the West. The US suspects Iran of wanting enrichment technology in order to become a nuclear state.
Earlier this year Russia's NATO ambassador Dmitry Rogozi, claimed that the Stuxnet malware had had an effect on Iran's Bushehr nuclear plant serious enough to cause equipment to malfunction, risking a second Chernobyl.
The effect of Stuxnet was to draw attention to the vulnerability of the industrial control systems targeted by the worm. The effects of the attack rumble on with frequent reports emerging of new vulnerabilities in this class of device.
Exactly who created Stuxnet remains unproven but the expert perception is that Israel was behind the malware, possibly aided by the US. In cybersecurity, where blame is often hard to apportion, perception can be powerful.
Iran has also blamed Israel for being behind Stuxnet but without offering much evidence. In late 2010, the country's authorities announced the arrest of "spies" accused of being involved in Stuxnet but their links with foreign powers, if any, were never detailed.