British media are reporting that both Russia and China have cracked top-secret information contained in files leaked by U.S. whistleblower Edward Snowden.
In 2013, Moscow granted asylum to Snowden, a former U.S. intelligence contractor who leaked details of government surveillance programs by American intelligence to the media.
The Sunday Times and the BBC reported on June 14 that British intelligence agents have been moved for their own protection.
Citing senior government sources, the British newspaper said the encrypted documents contain “details of secret intelligence techniques and information that could allow British and American spies to be identified.”
The BBC quoted a senior government source as saying the information obtained by Russia and China meant that "knowledge of how we operate" had stopped Britain getting "vital information."
An anonymous official from Britain's Home Office said that Russian President Vladimir Putin "didn't give [Snowden] asylum for nothing."
However, an official at Prime Minister David Cameron's office was quoted as saying that there was "no evidence of anyone being harmed."
The British government and intelligence services declined to comment.
The Russian and Chinese governments were not immediately available for comment.
The revelations came after senior lawyer David Anderson, the man responsible for reviewing Britain's antiterrorism laws, called on June 11 for greater judicial oversight over data interception amid efforts by the government to increase the powers of security services following Snowden's leaks.
After winning last month's general election outright, Prime Minister David Cameron's Conservative government is pushing ahead with legislation giving intelligence services and the police more powers to monitor Internet and phone use.
Anderson has called for new safeguards, including judges not ministers approving warrants for intrusive surveillance, and said there needed to be a compelling case for any extension of powers.
He concluded that the current situation was "undemocratic, unnecessary, and -- in the long run -- intolerable."
On June 14, Conservative lawmaker and former minister Andrew Mitchell said the timing of the report was "no accident."
He told BBC radio, "There is a big debate going on. We are going to have legislation brought back to parliament ... about the way in which individual liberty and privacy is invaded in the interest of collective national security."
Mitchell concluded, "That's a debate we certainly need to have."
With reporting by The Sunday Times and the BBC