The senior defense official spoke to The Associated Press anonymously because he was not authorized to speak on the record. He said the sole bin Laden shooter in the Pakistan compound was killed in the early minutes of the commando operation, the latest of the details becoming clearer now that the Navy SEAL assault team has fully been debriefed by officials.

As the raiders moved into the compound from helicopters, they were fired on by bin Laden's courier, Abu Ahmed al-Kuwaiti, who was in the guesthouse, the official said. The SEALs returned fire, and the courier was killed, along with a woman with him. The official said she was hit in the crossfire.

The Americans were never fired on again as they encountered and killed a man on the first floor of the main building and then bin Laden's son on a staircase, before arriving at bin Laden's room, the official said, revising an earlier account that the son was in the room with his father. Officials have said bin Laden was killed, shot in the chest and then the head, after he appeared to be lunging for a weapon.

White House and Defense Department and CIA officials through the week have offered varying and foggy versions of the operation, though the dominant focus was on a firefight that officials said consumed most of the 40 minutes on the ground after midnight Monday morning in Pakistan, Sunday in Washington.

"There were many other people who were armed ... in the compound," White House spokesman Jay Carney said Tuesday when asked if bin Laden was armed. "There was a firefight."

"We expected a great deal of resistance and were met with a great deal of resistance," he said.

"For most of the period there, there was a firefight," a senior defense official told Pentagon reporters in a briefing Monday.

White House counterterror adviser John Brennan originally suggested bin Laden was among those who was armed.

"He was engaged in a firefight with those that entered the area of the house he was in," Brennan said Monday, before the administration announced bin Laden actually was unarmed although weapons were in his room.

The success of the bin Laden raid gave the White House a spectacular story to offer without any need to dress it up. Some of the inconsistencies in the US accounts seemed designed to score extra propaganda points. Brennan, for one, using information that turned out to be flawed, portrayed bin Laden as a man "living in an area that is far removed from the front, hiding behind women who were put in front of him as a shield."

Officials soon dropped the contention that bin Laden tried to hide behind women. They said what really happened is that bin Laden's wife rushed the SEALs when they entered the room. They injured her with a shot in her calf.

The issue of who among the bin Laden group was armed can be a matter of interpretation. To a soldier, particularly in the case of the SEALs confronting the world's most wanted terrorist, an empty-handed person with a weapon nearby can be considered an armed threat.

The gaps and flaws, while striking, do not seem to approach the level of exaggeration and error in some other cases, such as the 2003 capture and eventual rescue of a female Army supply clerk in Iraq at the outset of the war. Initial military accounts of Jessica Lynch's resistance to her captors were part of an effort to rally public support for the war, and were factually wrong.