An Israeli military unit that undertakes cyberwarfare is responsible for creating a virus that attacked Iran's computer systems and stopped work at a nuclear power station, an expert has said. A Biblical reference has been detected in the code of the computer virus that points to Israel as the origin of the cyber attack.

Daily Telegraph Friday reported that the code contains the word “myrtus”, which is a reference to the myrtle tree. Myrtle's Hebrew word is Hadassah and it was the birth name of Esther, the Jewish queen of Persia. In the Bible, “The Book of Esther” tells how the queen persuaded her husband to launch an attack before being attacked themselves.

Israel has threatened a pre-emptive attack on Iran's facilities so that the Islamic state can't threaten its existence.

German researcher Ralf Langner claimed that the signals intelligence arm of the Israeli defence forces carried out the computer virus attack by infiltrating the software into Iran's Bushehr nuclear power station.

“If you read the Bible you can make a guess,” Langner was quoted as saying.

Experts have spent a long period of time to trace the origin of the Stuxnet worm, a malware that infected operating systems made by the German firm Siemens.

Those who are tracking Stuxnet worm believe that it was most likely introduced to Iran on a memory stick, possibly by one of the Russian firms that are helping to build Bushehr. The same firm has projects in Asia, including India and Indonesia which were also attacked.

Langner said: “It would be an absolute no-brainer to leave an infected USB stick near one of these guys and there would be more than a 50 percent chance of him pick it up and infect his computer.”

Cyber security experts said that Israel was the most likely perpetrator of the attack and had been targeting Iran but that it had not acknowledged a role to its allies.

“Nobody is willing to accept responsibility for this particular piece of malicious software which is a curious, complex and powerful weapon,” an expert was quoted as saying.