The protesters in Cairo appeared to be a genuinely spontaneous unarmed mob angered by an anti-Islam video said to have been produced in the United States. By contrast, it appeared the attackers in Benghazi were armed with mortars and rocket-propelled grenades. Intelligence reports are inconclusive at this point, officials said, but indications suggest the possibility that an organized group had either been waiting for an opportunity to exploit like the protests over the video or perhaps even generated the protests as a cover for their attack.

Max Fisher rounds up other analysis: