Attacked CIA base is key drone hub

The CIA base attacked by a suicide bomber in Afghanistan is at the heart of a covert program overseeing strikes by the agency's remote-controlled aircraft along the Afghanistan-Pakistan border, officials said Thursday.

The assailant, wearing an explosive belt under his clothes, was apparently allowed to enter Forward Operating Base Chapman after offering to become an informant, according to two former agency officials briefed on the attack.

The CIA declined to comment on the circumstances behind the attack, and it was unclear whether the bomber chose the base because of its role in supporting CIA airstrikes against top al-Qaida and Taliban leaders in the region.

The blast Wednesday in eastern Khost province killed seven CIA officers and contractors, including the base chief, a mother of three and a veteran of the agency's clandestine branch. The blast also seriously wounded six agency personnel in what intelligence officials described as a devastating blow to one of the agency's key intelligence hubs for counterterrorism operations.

It was the deadliest single day for the agency since eight CIA officers were killed in the 1983 bombing of a Marine barracks in Lebanon.

The CIA continued drone strikes today and Thursday. Pakistani intelligence officials said a U.S. missile strike destroyed a car carrying three men in a village near Mir Ali, which is a main town in North Waziristan.

It was the second such attack in the region in the last 12 hours. A U.S. drone missile strike late Thursday also killed three people.

The CIA deaths were formally acknowledged in a statement to employees Thursday by agency Director Leon Panetta, who said the heavy toll was a reminder of the "real danger" that confronts intelligence officers on the fronts of the two wars.

"Those who fell yesterday were far from home and close to the enemy, doing the hard work that must be done to protect our country from terrorism," Panetta said. "We owe them our deepest gratitude."

As is customary, the CIA declined to identify the victims. Earlier, a U.S. official briefed on the blast said eight U.S. civilians and an Afghan were killed.

President Obama posted a letter to CIA employees honoring those killed, whom he called "part of a long line of patriots who have made great sacrifices for their fellow citizens, and for our way of life."

U.S. personnel at Forward Operating Base Chapman are heavily involved in the selection of al-Qaida and Taliban targets for drone-aircraft strikes, according to two former intelligence officials. The drones are flown from separate bases in Afghanistan and Pakistan.

The base is also a center for recruiting and debriefing informants, the officials said, and it would not be unusual for local Afghans to be admitted to the facility for questioning.

A Taliban spokesman claimed responsibility Thursday for the bombing and said the bomber was an Afghan National Army officer who joined insurgents.

Material from The Associated Press is included in this report.