WASHINGTON -- Lawmakers in the U.S. House of Representatives have accused the fugitive national security contractor Edward Snowden of communicating with Russian security agencies while he is exiled in Moscow.

The accusations were contained in a classified House Intelligence Committee report, parts of which were released publicly on December 22. The evidence backing up the specific accusations about Snowden allegedly communicating with Russian agencies, however, remains classified.

Seen as a heroic whistle-blower by some, and a selfish traitor by others, Snowden in 2013 leaked 1.5 million documents he acquired while working as a contractor for the National Security Agency, the premier U.S. electronic surveillance agency. The materials prompted a furious public debate about the legality of some of the agency’s programs, about privacy concerns, and about U.S. snooping on its allies.

Snowden ended up flying to Hong Kong, and then to Moscow in June 2013, where he has lived in limbo since American authorities revoked his passport. U.S. prosecutors have charged him with violations of the 1917 Espionage Act.

Since that time, he has continued speaking about privacy concerns and made clear he wants to return to the United States if he gets certain legal protections.

Many in Congress, however, have excoriated him, and the newly declassified report by what is formally known as the Republican-led House Permanent Select Committee on Intelligence reflected that continuing anger.

"Snowden caused tremendous damage to national security, and the vast majority of the documents he stole have nothing to do with programs impacting individual privacy interests," the report said. They "instead pertain to military, defense, and intelligence programs of great interest to America's adversaries."

The report said that since his arrival in Moscow, Snowden "has had, and continues to have, contact with Russian intelligence services."

The report redacts the source for this assertion, saying it is classified. But it also cites a National Public Radio interview conducted in June with Frants Klintsevich, who is deputy chairman of the defense and security committee in Russia’s lower house of parliament. In the interview, Klintsevich was quoted as saying, "Let's speak frankly: I think that he did share intelligence. This is what security services do."

Snowden responded quickly to the report’s release, posting a series of messages to Twitter dismissing its findings:

Snowden’s case has generated sympathy among some privacy advocates, and his plight has been the focus of an Oscar-winning documentary and, more recently, a loosely fictionalized political thriller by renowned Hollywood director Oliver Stone.

In September, White House spokesman Josh Earnest brushed aside questions about whether Snowden might be pardoned by President Barack Obama, a call Stone made himself.

"Mr. Snowden should return to the United States and face the very serious charges that he's facing. He will, of course, be afforded the rights that are due to every American citizen in our criminal justice system, but we believe that he should return to the United States and face those charges," Earnest said.