A US intelligence committee report is calling National Security Agency leaker Edward Snowden a "serial exaggerator and fabricator'' who doesn't fit the profile of a whistleblower.
All members of the committee have sent a bipartisan letter to President Barack Obama urging him not to pardon Snowden.
Snowden's revelations about the agency's bulk collection of phone records set off a fierce debate that pitted civil libertarians concerned about privacy against lawmakers fearful about losing tools to combat terrorism.
"Mr. Snowden's claim that he stole this information and disclosed it to protect Americans, privacy and civil liberties is undercut by his actions,'' the letter says.
"Rather than avail himself of the many lawful avenues to express legal, moral, or ethical qualms with US intelligence activities, Mr. Snowden stole 1.5 million classified documents from National Security Agency networks.''
Snowden was an NSA contract employee when he took the documents and leaked them to journalists who revealed massive domestic surveillance programs begun in the aftermath of the September 11 attacks. The programs collected the telephone metadata records of millions of Americans and examined emails from overseas.
Snowden fled to Hong Kong, then Russia, to avoid prosecution and now wants a presidential pardon because he says he helped his country by revealing secret domestic surveillance programs.
Ben Wizner, Snowden's lawyer at the American Civil Liberties Union, said the committee's report was an attempt to discredit a "genuine American hero.''
"After years of investigation, the committee still can't point to any remotely credible evidence that Snowden's disclosures caused harm,'' Wizner said.
Speaking by video link from Moscow, Snowden said on Wednesday that whistleblowing "is democracy's safeguard of last resort, the one on which we rely when all other checks and balances have failed and the public has no idea what's going on behind closed doors.''
The report was released one day ahead of Friday's opening of director Oliver Stone's film Snowden.
