Snowden has NSA blueprints 'but will not leak them'

Edward Snowden has highly sensitive documents on how the US National Security Agency is structured and operates that could harm the US government, but has insisted that they not be made public, a journalist close to the NSA leaker said.

Glenn Greenwald, a columnist with The Guardian who first reported on the intelligence leaks, said disclosure of the information in the documents "would allow somebody who read them to know exactly how the NSA does what it does, which would in turn allow them to evade that surveillance or replicate it". The "literally thousands of documents" taken by Snowden constituted "basically the instruction manual for how the NSA is built".

To take documents with him that proved what he was saying was true he had to take ones that included very sensitive, detailed blueprints of how the NSA does what it does, the journalist said.

Greenwald believed disclosure of the documents' information would not prove harmful to Americans or their national security, but that Snowden had insisted they not be made public.

"I think it would be harmful to the US government, as they perceive their own interests, if the details of those programmes were revealed," he said.