About three hours after the U.S. diplomatic mission in Benghazi, Libya, came under attack, the Pentagon issued an urgent call for an array of quick-reaction forces, including a Special Forces team that was on a training mission in Croatia.

The team dropped what it was doing and prepared to move to the Sigonella naval air station in Sicily, a short flight from Benghazi and other hot spots in the region. By the time the unit arrived at the base, however, the surviving Americans at the Benghazi mission had been taken to Tripoli, and Ambassador Chris Stevens and the three others were dead.

The episode described by several U.S. officials points to a limitation in the capabilities of the U.S. military command responsible for Africa, including the North African countries swept up in the Arab Spring. Africa Command, established in 2007 as the Pentagon's newest four-star regional headquarters, did not have on hand what every other regional combatant command has: its own force with the ability to respond rapidly to emergencies -- a Commanders' In-Extremis Force, or CIF. To respond to the Benghazi attack, the Africa Command had to borrow the CIF of the European Command, because its own force is still in training. It also had no AC-130 gunships or armed drones available. At the heart of the issue is the Africa Command, which has been building its team from scratch, and its nascent strike force was training in the United States on Sept. 11, a senior military official said. Because of African sensitivities about an overt U.S. military presence, the command's headquarters was established near Stuttgart, Germany. "The conversation about getting them closer to Africa has new energy," the military official said.