An investigation of the attacks on the American diplomatic mission and nearby annex in Benghazi, Libya, last year is looking at more than five potential suspects, a U.S. national security source said on Wednesday.
The source would not identify the suspects who have come to the attention of the FBI, which is investigating the Sept. 11, 2012, attacks that killed the U.S. ambassador to Libya and three other Americans.
State Department spokesman Patrick Ventrell declined to comment on specifics of the investigation, but said: "There's no one more than the State Department family that wants to see justice served for these heinous crimes."
A Justice Department spokesman would not comment because "our investigation is ongoing."
The FBI had previously released photographs of three men who the law enforcement agency said were at the U.S. diplomatic mission in Benghazi when it was attacked.
The FBI did not call them suspects but said they may be able to provide information to help in the investigation.
The Benghazi attacks have touched off political warfare on Capitol Hill, with Republicans accusing President Barack Obama's administration of telling shifting stories about who was behind the attacks. Democrats accuse Republicans of politicizing a tragedy.
Militants believed to have ties to al Qaeda affiliates attacked a loosely guarded U.S. diplomatic compound and a nearby CIA annex in the eastern Libyan city of Benghazi on Sept. 11, the anniversary of the 2001 attacks on the United States.
Separately on Wednesday, retired Ambassador Thomas Pickering reached an agreement with Darrell Issa, the chairman of the House Oversight Committee, that means he no longer faces a subpoena to sit for a taped deposition with the panel's staff on Thursday.
Pickering, the co-chairman of a board that investigated Benghazi, will now sit for the interview to discuss his findings at a later date that has not yet been set, Issa said.