The former National Security Agency contractor on the run from U.S. authorities halfway around the world said that Stuxnet, an unprecedented cyber weapon that targeted Iran's nuclear program, was the product of a joint American-Israeli secret operation.

Before Edward Snowden became a household name, he conducted an interview via encrypted emails with cyber security expert Jacob Appelbaum and was asked about the game-changing computer code, according to the interview published in the German newspaper Der Spiegel Monday.

"NSA [U.S. National Security Agency] and Israel co-wrote it," Snowden said.

Snowden said that the NSA regularly works with foreign governments and has a "massive body" called the Foreign Affairs Directorate to deal with international partners.

In the interview Snowden did not discuss Stuxnet further and, so far, none of the newspapers Snowden has worked with have published any documents directly relating to the cyber weapon.

Discovered in 2010 but possibly in action as early as 2005, Stuxnet was designed to infiltrate the computer system at an Iranian nuclear facility, physically damage the facility's infrastructure by throwing off automated systems and cover its tracks so that even if engineers were monitoring those systems, everything would appear normal.

At the time of its discovery, cyber security experts put the U.S. and Israel on a short list of nations capable of developing such a sophisticated and expensive cyber weapon. In June 2012, The New York Times reported Stuxnet was part of a cyber offensive program begun under President Bush and accelerated by President Obama which targeted Iran's nuclear program and said Stuxnet was "developed by the United States and Israel." No U.S. or Israeli officials have gone on the record to claim responsibility for Stuxnet or its digital successors.

Snowden remains holed up on the transit side of Moscow's Sheremedevo International Airport. He has been unable to travel since he arrived there from Hong Kong more than two weeks ago because the State Department canceled his passport. He has also managed to remain out of sight since his arrival.

Snowden has been searching for a safe haven where he can evade U.S. charges of espionage. Venezuela has said it would grant Snowden political asylum, but it remains unclear how he will be able to travel to the South American nation from Moscow without having to stop in a country that holds an extradition treaty with the U.S. There are no direct commercial flights to Venezuela's capital of Caracas.