The National Security Agency (NSA) has released an email that it says distances it from Edward Snowden's claims that he voiced his concerns on the legality of the PRISM spying programme before turning to the media to expose it.
It said it had one official email from Snowden and it was a follow-up question that concerned some training that he had completed.
"NSA has now explained that they have found one email inquiry by Edward Snowden to the Office of General Counsel asking for an explanation of some material that was in a training course he had just completed," it explained.
"The email did not raise allegations or concerns about wrongdoing or abuse, but posed a legal question that the Office of General Counsel addressed. There was not additional follow-up noted.
"There are numerous avenues that Mr Snowden could have used to raise other concerns or whistleblower allegations. We have searched for additional indications of outreach from him in those areas and to date have not discovered any engagements related to his claims."
Earlier this week, in an interview with US broadcaster NBC, Snowden said that he made many approaches on his superiors, and only went public when these attempts failed.
"I would say one of my final official acts in government was continuing one of these communications with a legal office," he said. "I'm so sure that these communications exist that I've called on Congress to write a letter to the NSA to verify that they do."
Furthermore, in an interview with the Washington Post carried out after the NSA's release Snowden claimed that the release from the NSA was "incomplete" and there was more evidence out there that could be made public.
"If the White House is interested in the whole truth, rather than the NSA's clearly tailored and incomplete leak today for a political advantage, it will require the NSA to ask my former colleagues, management, and the senior leadership team about whether I, at any time, raised concerns about the NSA's improper and at times unconstitutional surveillance activities. It will not take long to receive an answer."
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