FBI director Robert S. Mueller III today disclosed that the FBI is investigating leaks to the news media about the recently disrupted plot by Al Qaeda's Yemen affiliate to smuggle a bomb designed to be concealed in underwear onto a U.S. bound jet.

The plans for the attack, which featured a more sophisticated version of the device the "underwear bomber" of Christmas 2009 was arrested with, were first revealed by the AP. But a day later, it was revealed that the individual at the center of the plot was a double agent working for Britain's MI-6 secret intelligence service and the CIA along with Saudi Arabian intelligence assets.

"We have initiated an investigation into this leak," Mueller testified before the Senate Judiciary Committee on Wednesday.  "Leaks such as this threaten ongoing operations, puts at risk the lives of sources, makes it much more difficult to recruit sources, and damages our relationships with our  foreign partners."

"Leaks such as this have a - I don't want overuse the word 'devastating' - but have a huge impact on our ability to do our business, not just on a particular source and the threat to the particular source, but your ability to recruit sources is severely hampered," Mueller said, describing the implications of the leak of sensitive national security information.

Mueller continued, "In cases such as this, your - the  relationship with your  counterparts overseas are damaged and which means that an inhibition in the willingness of others to share  information with us where they don't think that information will remain secure.  So it also has some long-term effects, which is why it is so important to make certain that the persons who are responsible for the leak are brought to justice."

The investigation is likely being run by the Justice Department's counterespionage section and agents from the FBI's Washington Field Office.

Justice Department officials and an FBI spokesman declined to comment on the nature of the investigation. The CIA also declined comment.

The Office of the Director of National Intelligence is also conducting a review with the DNI's general counsel to see if the leaks originated in any of the 16 agencies that DNI James Clapper oversees.

Earlier in the day Matthew Olsen, director of the National Counterterrorism Center, addressed the issue of media leaks relating to the plot and called it "devastating."

"Leaks do endanger people's lives … that is not an exaggeration," Olsen said, speaking before the American Bar Association's standing Committee on Law and National Security, in Washington, D.C.