NSA whistleblower Snowden confirms the NSA jointly developed the Stuxnet computer virus with Israel to take down an Iranian nuclear facility.
While it has been widely speculated that Stuxnet was the result of a partnership between the US and Israel ever since the computer worm was discovered in 2010, the US government has never officially taken responsibility for it.
Asked whether the NSA collaborates with Israel, Snowden said: "Yes, all the time. The NSA has a large section for that, called the FAD - Foreign Affairs Directorate." When asked specifically about Stuxnet, Snowden confirmed: "The NSA and Israel wrote Stuxnet together."
Stuxnet was a highly complex computer program which was designed to specifically target a uranium enrichment facility in Natanz, Iran which the US and Israel believed was being used to help Iran develop nuclear weapons. Iran denied this accusation, saying it was being used to help create nuclear power stations.
Stuxnet was designed to make the centrifuges spin out of control and cause physical damage to the plant in Natanz - which it succeeded in doing during 2009.
According to sources who spoke to the New York Times reporter David Sagner last year, Stuxnet was developed under the a top secret programme called Olympic Games which was started under President George W. Bush and continued during President Barack Obama's administration.
Stuxnet was never meant to be released into the wild but it was, and as a result infected millions of PCs around the world and lead to its discovery by security company VirusBlokAda in June 2010.
Last year an even more complex computer virus called Flame was discovered and while initially it was not linked to Stuxnet, further investigation by Kaspersky Labs identified a module within both which indicated that the writers of Flame were the same as those behind Stuxnet.
Flame has been described by security experts as one of the most complex pieces of malware ever discovered and allowed those who created it to search for and upload documents and files on a remote computer, watch and listen to what's taking place around the infected PC by turning on the camera or microphone, and even copy the address book from mobile phone within range of the computer.
Flame was discovered to be infecting computers in the Middle East, in countries such as Iran, Israel and Sudan, with the majority of infected computers, according to Kaspersky's data, being in Iran.
As well as confirming the NSA's collaboration with Israel over Stuxnet, Snowden also confirmed in the interview in Der Spiegel that the NSA was "in bed with the Germans, just like with most other Western states."
This would seem to contradict German Chancellor Angela Merkel who said she was surprised by the spying allegations.
"Other agencies don't ask us where we got the information from and we don't ask them. That way they can protect their top politicians from the backlash in case it emerges how massively people's privacy is abused worldwide," Snowden said.