A House intelligence committee report issued on Thursday condemned Edward Snowden, saying the National Security Agency leaker is not a whistleblower and accused him of leaking secrets that 'caused tremendous damage' to U.S. security.

The report also indicated that the vast majority of the documents he stole were defense secrets that had nothing to do with privacy.

The Republican-led committee released a three-page unclassified summary of its two-year bipartisan examination of how Snowden was able to remove more than 1.5 million classified documents from secure NSA networks, what the documents contained and the damage their removal caused to U.S. national security.

Scroll down for video

A scathing House intelligence committee report issued on Thursday condemned Edward Snowden (pictured), saying the National Security Agency leaker is not a whistleblower and accused him of leaking secrets that 'caused tremendous damage' to U.S. security

The National Security Agency campus in Fort Meade, Maryland shown above. Snowden, 33, was an NSA contract employee when he took the documents and leaked them to journalists

The committee said while the 'full scope' of damage caused by Snowden's disclosures remains unknown, a review of materials he allegedly compromised 'makes clear that he handed over secrets that protect American troops overseas and secrets that provide vital defenses against terrorists and nation-states.'

Snowden, 33, 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 9/11 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 as a whistleblower.

Rep. Devin Nunes, R-Calif., chairman of the committee, said Snowden betrayed his colleagues and his country.

'He put our service members and the American people at risk after perceived slights by his superiors,' Nunes said in a statement.

'In light of his long list of exaggerations and outright fabrications detailed in this report, no one should take him at his word.

'I look forward to his eventual return to the United States, where he will face justice for his damaging crimes.'

Snowden's revelations about the agency's bulk collection of millions of Americans' phone records set off a fierce debate that pit civil libertarians concerned about privacy against more hawkish lawmakers fearful about losing tools to combat terrorism.

Democrats and libertarian-leaning Republicans pushed through a re-authorization of the USA Patriot Act last year that ended the program.

There was little evidence that the phone records or other surveillance programs Snowden revealed ever thwarted an attack.

Snowden is seeking a presidential pardon because he says he helped his country by revealing secret domestic surveillance programs.

Separately, all members of the committee sent a bipartisan letter to President Barack Obama urging him not to pardon Snowden.

Dinah PoKempner, left, general council for Human Rights Watch, listens as Edward Snowden speaks on a television screen via video link from Moscow during a news conference on Wednesday to call upon President Barack Obama to pardon Snowden before he leaves office

'The vast majority of what he took has nothing to do with American privacy,' said Rep. Adam Schiff of California, the ranking Democrat on the House intelligence committee.

'The majority of what he took has to do with military secrets and defense secrets,' Schiff said in an interview Thursday for C-SPAN's Newsmakers.

'I think that's very much at odds with the narrative that he wants to tell that he is a whistleblower.'

The Obama administration has urged Snowden to return to the U.S. and face trial.

Justice Department spokesman Marc Raimondi has said 'there is no question his actions have inflicted serious harms on our national security.'

Snowden was a 'disgruntled employee who had frequent conflicts with his managers,' according to the committee report.

Publicly revealing classified information does not qualify someone as a whistleblower, the report said.

Demonstrators hold placards supporting former US intelligence analyst Edward Snowden during a protest against government surveillance in 2013 in Washington, DC

The committee 'found no evidence that Snowden took any official effort to express concerns about U.S. intelligence activities to any oversight officials within the U.S. government, despite numerous avenues for him to do so.'

Snowden began mass downloads of classified material two weeks after he was reprimanded for engaging in a spat with NSA managers, according to the committee.

The committee also described Snowden as a 'serial exaggerator and fabricator.'

'A close review of Snowden's official employment records and submissions reveals a pattern of intentional lying,' the report said.

'He claimed to have left Army basic training because of broken legs when in fact he washed out because of shin splints.

'He claimed to have obtained a high school degree equivalent when in fact he never did. '

Snowden also claimed to have worked for the CIA as a senior adviser, when he was a computer technician, the report said.

'He also doctored his performance evaluations and obtained new positions at NSA by exaggerating his resume and stealing the answers to an employment test,' the report said.

Actress Melissa Leo and actors Joseph Gordon-Levitt, Tom Wilkinson and Ewen MacAskill are pictured in a scene from Oliver Stone's film Snowden, which opens on Friday

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 33-year-old addressed a New York City news conference where advocates from the American Civil Liberties Union, Human Rights Watch and Amnesty International announced an online petition drive to urge Obama to pardon Snowden before he leaves office.

The supporters called Snowden a hero for exposing the extent of government surveillance by giving thousands of classified documents to journalists.

Snowden insists he has not shared the full cache of 1.5 million classified documents with anyone.

However, the report notes that in June, the deputy chairman of the Russian parliament's defense and security committee publicly conceded that 'Snowden did share intelligence' with his government.