Washington: The Obama administration and former intelligence contractor Edward Snowden offered divergent accounts on Thursday of his efforts to raise concerns about National Security Agency activity more than a year ago, as each side tried to shape the debate over whether the massive leak of classified information was avoidable.

Intelligence officials released a brief email that Mr Snowden wrote in April last year inquiring about legal authorities but raising no concerns about any particular NSA program or law. The suggestion was that the email did not make Snowden a whistleblower. US officials said the NSA had found no other evidence that he had expressed concerns to anyone in a position of authority or oversight.

But in an email to The Washington Post, Mr Snowden, who last year leaked large quantities of classified documents to journalists and who is living in Russia under temporary asylum, called the official release "incomplete."

He said it did not include his correspondence with NSA compliance officials and concerns he had raised about "indefensible collection activities". He repeated claims that he had shown colleagues "direct evidence" of programs that they agreed were unconstitutional.