Marie Harf said at a Washington news briefing, though, that those who carried out the attack that killed four Americans, including U.S. ambassador to Libya Chris Stevens, may "have taken inspiration from al-Qaida ideology, certainly, [and] that's what the investigation is looking into."
She added the FBI is continuing the investigation.
Her comments came after the New York Times, in an article Sunday, reported there was no link between al-Qaida and the militants who stormed the mission.
"We do know, as we've said from the beginning, that extremists were involved. These folks don't carry ID cards. They don't come out and wear a T-shirt that says, 'I belong to al-Qaida,'" she added.
Notable deaths of 2014 [PHOTOS]