Investigative journalist Glenn Greenwald, who first published details of US surveillance provided by Edward Snowden, has backed German calls for the NSA whistleblower to testify before a Bundestag inquiry.
Without the information provided by Mr Snowden, he said, German intelligence services would not have known the NSA had tapped Chancellor Angela Merkel’s mobile for over a decade until earlier this year.
Mr Greenwald said further NSA spying revelations were in the pipeline, he said, concerning Germany and other countries.
“It makes sense to question Snowden: he is very courageous and wants to talk about what he knows about [US] spying on allies and innocent citizens,” said Mr Greenwald to German public broadcaster ARD. “Also, he has huge experience in these practices because he worked for many years in the system. But he won’t do it for nothing, not unless the German government acts to protect his fundamental rights.”
Germany's Social Democratic, Green and Left Parties have backed requests to call Mr Snowden as a witness in a parliamentary inquiry. Left Party floor leader Gregor Gysi suggested the 30-year-old, currently living in an undisclosed location in Russia, should be placed in Germany's witness protection programme.
On Monday night President Barack Obama said on television that US intelligence services had "continued to develop and expand" over the years and that he was "initiating a review" of their operations.
“National security operations generally have one purpose and that is to make sure that the American people are safe,” he said.
However Mr Greenwald, who recently announced his move from the Guardian to a new media venture, dismissed this claim.
"Far more than that it is about securing economic advantages," he told German television. Recent revelations in Brazil, where he lives, showed that US intelligence spied on economic conferences, oil companies and the energy ministry.
“It’s definitely just about the industrial and economic advantage,” said Mr Greenwald. “It has nothing to do with national security and definitely nothing to do with terrorism.”
The New York Times, citing unnamed government sources, said the NSA did not just collect so-called metadata – phone numbers called, length of call – but actually listened in on calls made by Dr Merkel on her unencrypted mobile phone.
Until now the US government has declined to confirm or deny that the NSA tapped Dr Merkel’s phone in the past. Obama administration officials have denied the president knew of the practice, contradicting German media reports that he did.
Germany’s acting interior minister Hans-Peter Friedrich has vowed to track down and deport anyone involved in tapping the German leader’s phone.
"Those responsible have to be found and brought to justice," he told German television, ahead of a visit to Washington to discuss the latest NSA allegations. "It wouldn't be the first time diplomats from that country have been expelled."
German investigators are pessimistic the allegations will ever be cleared up. In particular, they do not expect to be granted permission to enter the US embassy adjacent to the Brandenburg Gate to investigate claims it hosts an illegal listening post.