WASHINGTON — About three hours after the US diplomatic mission in Benghazi, Libya, came under attack, the Pentagon issued an urgent call for an array of quick-reaction forces, including an elite 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 evacuated to Tripoli, and Ambassador J. Christopher Stevens and three other Americans were dead.
The assault, on the anniversary of the Sept. 11, 2001, attacks on the United States, has exposed shortcomings in the Obama administration’s ability to secure diplomatic missions and act on intelligence warnings.
But this previously undisclosed episode, described by several US officials, points to a limitation in the capabilities of the American 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 .
To respond to the Benghazi attack, the Africa Command had to borrow the Commanders’ In-Extremis Force of the European Command, because its own force is still in training. It also had no AC-130 gunships or armed drones readily available that night.
As officials in the White House and Pentagon scrambled to respond to the torrent of reports pouring out from Libya — with Stevens missing and officials worried that he might have been taken hostage — they also took the extraordinary step of sending the elite Delta Force, with its own helicopters and ground vehicles, from its base at Fort Bragg, N.C., to Sicily. Those troops also arrived too late.
‘‘The fact of the matter is these forces were not in place until after the attacks were over,’’ a Pentagon spokesman, George Little, told reporters on Friday. ‘‘We did respond. The secretary ordered forces to move. They simply were not able to arrive in time.’’
At the heart of the issue is the Africa Command, which was spun off from the European Command. At the time it was established, the Pentagon thought it would be mostly devoted to training African troops and building military ties with African nations.
Because of African sensitivities about an overt US military presence in the region, the command’s headquarters was established near Stuttgart, Germany.
While the other regional commands, including the Pacific Command and the Central Command, responsible for the Middle East and South Asia, have their own specialized quick-reaction forces, the Africa Command has had to borrow the European Command’s force when trouble has struck on the continent.
Africa Command has been building its own team from scratch, and its nascent strike force was training in the United States on Sept. 11, a senior military official said.
Some Pentagon officials said it was unrealistic to think a quick-reaction force could have been sent in time even if the African Command had one ready to act at Sigonella when the Benghazi attack unfolded, and asserted that such a small force might not have even been effective or the best means to protect an embassy.
A spokesman for the command declined to comment on how its capabilities might be improved.
The Africa Command is led by General Carter F. Ham, an infantryman who commanded a brigade in Mosul during the Iraq war and took charge of the headquarters last year, just before American, British, and French air power helped topple Moammar Khadafy in Libya.
On day of the attacks on the mission and a nearby annex in Benghazi, Ham and other regional commanders were in Washington for a series of long-planned meetings.
The Pentagon national military command center distributed a report around 4:30 p.m., 50 minutes after the assault started, that there had been violence in Benghazi and the ambassador could not be located. But military forces were too far away or could not be mobilized in time to help.