Washington, September 16 (RHC)-- A U.S. congressional intelligence committee has released a report condemning intelligence whistleblower Edward Snowden for leaking information that "caused tremendous damage" to U.S. national security and urging President Barack Obama not to pardon him. 

The House of Representatives intelligence committee issued the scathing report Thursday, saying that Snowden was -- in their words -- "not a whistleblower" as he has claimed.  The report was endorsed by both its Republican and Democratic leaders. 

The congressional report claims that most of the material Snowden stole from the National Security Agency (NSA) while he worked at the spy agency was not about invasions of privacy, but disclosed intelligence and military programs of great interest to U.S. adversaries. 

Snowden leaked thousands of classified intelligence documents in June 2013, revealing the extent of the NSA's spying activities, including the massive collections of phone records of Americans and foreign nationals as well as political leaders around the world. 

On Wednesday, several prominent human rights organizations urged Obama to pardon Snowden before leaving the White House in January.  However, the Obama administration has urged Snowden to return to the U.S. and face trial, saying there is no doubt that he inflicted serious harm on the U.S. national security.

His asylum in Moscow has been a source of tension between the United States and Russia, with the U.S. president canceling a planned meeting with Russian President Vladimir Putin at the G-20 Summit in 2013 after Russia agreed to let him in.