Former US defence contractor Edwards Snowden may have leaked to journalists as many as 200,000 sensitive documents beloging to the US National Security Agency that detail spying efforts by intelligence agencies.

The news was revealed in remarks made by NSA chief General Keith Alexander during a recent question and answer session to a US foreign affairs group.
The Snowden document trove was far smaller than the cache obtained by whistleblower group Wikileaks which included some 400,000 reports from the Pentagon along with 250,000 diplomatic cables.
But the NSA documents were more sensitive with some marked 'special intelligence' and many more labelled top secret. None of the Wikileaks cables were labelled higher than secret.