Deputy Secretary of State William J. Burns (left), who is in charge of policy, and Deputy Secretary of State Thomas Nides (second from left), who is in charge of management, leave a hearing room on Capitol Hill in Washington on Thursday, Dec. 20, 2012, after testifying before the Senate Foreign Relations Committee about the attack on the U.S. Consulate in Benghazi, Libya, in which the U.S. ambassador and three other Americans were killed on Sept. 11. Secretary of State Hillary Rodham Clinton had been scheduled to testify but canceled after fainting and sustaining a concussion last week. (AP Photo/J. Scott Applewhite)

Photo by: J. Scott Applewhite

Deputy Secretary of State William J. Burns (left), who is in charge of policy, and Deputy Secretary of State Thomas Nides (second from left), who is in charge of management, leave a hearing room on Capitol Hill in Washington on Thursday, Dec. 20, 2012, after testifying before the Senate Foreign Relations Committee about the attack on the U.S. Consulate in Benghazi, Libya, in which the U.S. ambassador and three other Americans were killed on Sept. 11. Secretary of State Hillary Rodham Clinton had been scheduled to testify but canceled after fainting and sustaining a concussion last week. (AP Photo/J. Scott Applewhite)