Sen. Carl Levin, Democratic chairman of the Senate Armed Services Committee, said the Pakistani Army and intelligence agency "have a lot of questions to answer, given the location, the length of time and the apparent fact that this was actually - this facility was actually built for bin Laden, and its closeness to the central location of the Pakistani army."

Besides bin Laden, one of his sons, Khalid, was killed in the raid, as was the wife who shielded him, Brennan said. Also killed were two of bin Laden's al-Qaida facilitators, including one who was apparently listed as the owner of the residence, Brennan said.

Obama gave preliminary orders for the attack on Friday shortly before flying to Alabama to inspect tornado damage, and aides set to work on the details. He gave the final directive Sunday. Brennan called it one of the "gutsiest calls of any president in recent memory."

Brennan said the president and his national security team monitored the raid from the White House Situation Room and expressed relief that elite forces had finally gotten bin Laden without losing any more American lives.

"It was probably one of the most anxiety-filled periods of time in the lives of the people who were assembled here," Brennan said. "The minutes passed like days."

Brennan strongly suggested a live video feed had been available - SEALs customarily have video cameras attached to their helmets - and the White House released a photo showing the commander in chief, Vice President Joe Biden and top aides staring intently at something outside the picture. The White House did not say what they were looking at.

The dramatic developments came just months ahead of the 10-year anniversary of the hijacked-airliner assaults on the United States. Those attacks took nearly 3,000 lives, led the US into war in Afghanistan and Iraq and forever pierced the notion that the most powerful country on earth could not be hit on such a ferocious scale.

Officials say CIA interrogators in secret overseas prisons in Eastern Europe developed the first strands of information that ultimately led to the killing of bin Laden. Intelligence officials have long known that bin Laden trusted one al-Qaida courier in particular, and they believed he might be living with him in hiding. Four years ago, the United States learned the man's identity, which officials did not disclose, and then about two years later, they identified areas of Pakistan where he operated. Last August, the man's residence was found, officials said.

By mid-February, intelligence from multiple sources was clear enough that Obama wanted to pursue action, a senior administration official said. Over the next two and a half months, the president led five meetings of the National Security Council focused solely on whether bin Laden was in that compound and, if so, how to get him, the official said.

Once under way, four helicopters ferried the US forces to the Abbottabad compound, lowered the SEALS behind the walls and began descending toward a landing. No shots were fired, but shortly after the team hit the ground, one of the helicopters came crashing down and rolled onto its side for reasons the government has yet to explain. None of the SEALs was injured, however, and the mission continued uninterrupted. The crippled aircraft was destroyed before the raiding party flew out in the three remaining helicopters.