Iran is accusing German engineering company Siemens of aiding a cyber attack on the country's nuclear facilities, and is demanding legal action.

Gholamreza Jalali, head of Iran's civilian defense forces, has accused German engineering company Siemens of helping the United States and Israel launch a cyber attack on its nuclear facilities, according to Iran's Islamic Republic News Service. Jalali said the Stuxnet worm was the work of Iran's two most powerful and consistent enemies and that Siemens must take some of the responsibility. He said the Iranian government plans to seek remedies in the courts.

The investigations show the source of the Stuxnet virus originated in America and the Zionist regime [Israel], Jalali was quoted as saying. The Foreign Ministry and other relevant political and judicial organizations should lodge complaints at international courts... The attacking countries should be held legally responsible for the cyberattack. Jalali said the Stuxnet sent reports on infected systems to computers in Texas.

Besides Jalali's accusations, other evidence has emerged that could point to an Israeli origin - or at least prior knowledge - of the Stuxnet worm. In February, a retirement party video for Israeli General Gabi Ashkenazi surfaced that noted the successes of the Israeli Defense Forces, and mentioned Stuxnet.

Stuxnet is designed to infect and give commands relayed from its creator to industrial control systems, known as Supervisory Control and Data Acquisition. Stuxnet infects computers via removable drives, such as USB sticks or a CD. It replicates over local networks by exploiting vulnerability in Microsoft server systems.

It isn't entirely clear what kind of damage Stuxnet did in Iran, as Iranian officials haven't given details. Symantec, a firm that makes antivirus software, issued a report in February that said one of Stuxnet's targets is centrifuge control systems, which could mean that the virus was intended to disrupt Iran's uranium enrichment program.

Jalali said the consequences of Stuxnet might have been more serious, given that the worm infected computers at the nuclear facilities in Natanz and Busehr.

The earliest variants of Stuxnet were seen in 2009. Symantec says that it has found 100,000 infected computers and the vast majority are in Iran. The report says the Stuxnet worm was a directed attack on five specific organizations. All of them have a presence in Iran.

Siemens did not comment on Jalali's accusations.