Britain's MI6 intelligence agency was forced to withdraw tens of spies overnight Saturday/Sunday, after Russian and Chinese agents cracked one million top-secret files released by National Security Agency (NSA) whistleblower Edward Snowden.
Sources from Downing Street, the Home Office, and security services confirmed to several British news outlets that the documents contained sensitive identifying details for tens of British and American spies. Spies at risk are being withdrawn immediately.
A senior Home Office official has accused Snowden of having 'blood on his hands' for the move, according to the Daily Mail.
"Snowden has done incalculable damage," a British intelligence source told the Sunday Times. "In some cases the agencies have been forced to intervene and lift their agents from operations to prevent them from being identified and killed."
"We know Russia and China have access to Snowden's material and will be going through it for years to come, searching for clues to identify potential targets."
However, officials at Prime Minister David Cameron's office downplayed the threats, saying that there is no current evidence that the information will be used against intelligence agents.
Snowden, a former NSA contractor, is wanted by the United States on espionage charges after leaking a mass of secret NSA documents.
The 31-year-old fugitive is in asylum in Russia, where he has been granted a three-year residency that allows him to travel abroad.
American intelligence agencies have yet to comment on the development.