The director of the U.S. Federal Bureau of Investigation, Robert Mueller, is vowing to take swift action against the former CIA analyst who has confessed to leaking documents exposing a pair of top secret government surveillance programs.
Speaking to lawmakers Thursday, FBI chief Mueller confirmed that a criminal investigation has been opened into the leaks, which he said have dealt a blow to U.S. national security.
"These disclosures have caused significant harm to our nation and to our safety. We are taking all necessary steps to hold the person responsible for these disclosures."
He did not mention the name of the confessed leaker, Edward Snowden, who is currently in Hong Kong, from where he has vowed to fight any attempt to extradite him to the U.S. to face charges.
Mueller defended the surveillance programs, saying they are a legal and crucial tool in preventing terrorist attacks. He said their disclosure could prompt potential terrorists to change their behavior and become more difficult to track.
General Keith Alexander, the head of the National Security Agency, says the programs carried out by his agency have helped foil dozens of terrorist attacks. Lawmakers say the NSA will soon present details on this claim.
Meanwhile, Snowden, an ex-NSA contractor, continues to speak with media outlets from Hong Kong. In his latest interviews, Snowden has moved beyond criticizing the domestic spying programs, and is now also focusing on what he says are widespread U.S. hacking attempts against foreign targets.
On Wednesday, he told the South China Morning Post the NSA has been hacking computers in Hong Kong and mainland China since 2009, with targets including public officials, businesses and the Chinese University of Hong Kong.
The revelation threatens to further complicate relations between China and the United States, which have already been trading increasingly fierce accusations on cyber hacking and espionage.
For the second straight day, Chinese state media, which often reflect official opinion, devoted a considerable amount of coverage to the issue.
An editorial in the Communist Party-controlled Global Times said Beijing deserves an explanation from the U.S. on the alleged hacking attempts. It said Chinese officials should try to acquire more information from Snowden and "use it as evidence to negotiate with the U.S."
So far, there is no evidence Beijing officials have sought out any such information from Snowden, who is in an unknown location in Hong Kong, a semi-autonomous sovereign territory of China.
But the editorials now suggest Beijing would be willing to use the leaks to deflect pressure from Washington, which had attempted to hold China accountable for its alleged hacking attacks on U.S. targets.
A series of recent private and official reports have accused Chinese hackers of stealing information, ranging from the designs for dozens of top U.S. weapons systems to other trade secrets and commercial data that would benefit Chinese businesses.