The Stuxnet virus was planted at the Natanz nuclear facility by “an Israeli proxy” using a corrupt memory stick, former and serving US intelligence officials told the Industrial Safety and Security Source website.

The unnamed sources said a saboteur used a memory stick to infect the machines at Natanz nuclear facility.

In October 2010, Iran’s Intelligence Minister Heydar Moslehi said an unspecified number of nuclear spies were arrested in connection with the virus.

The Americans said the insider was a member of the terrorist Mujahedin-e Khalq Organization (MKO).

Former head of the CIA Counterterrorism Vince Cannistraro said Israel is using the MKO as the assassination arm of its spy agency, Mossad, for targeted killings of Iranian scientists.

He said the MKO is in charge of executing “the motor attacks on Iranian targets chosen by Israel. They go to Israel for training, and Israel pays them.”

Stuxnet, first indentified by the Iranian officials in June 2010, is a malware designed to infect computers using Siemens supervisory control and data acquisition (SCADA) -- a control system favored by industries that manage water supplies, oil rigs, and power plants.

In July 2010, media reports claimed that Stuxnet had targeted industrial computers around the globe, with Iran being the main target of the attack. They said the country's Bushehr nuclear power plant was at the center of the cyber attack. //presstv