The commandos encountered gunshots from only one man, whom they quickly killed, before sweeping the house and shooting others, who were unarmed, a senior defence official said in the latest account.
In yesterday's revised telling, the Navy SEALs mounted a precision, floor-by-floor operation to find the al-Qaeda leader and his protectors - but without the prolonged and intense firefight that officials had described for several days.
US officials said some of the first information gleaned from the scene indicated that last year al-Qaida was considering attacking US trains on the tenth anniversary of the September 11 attacks. The officials said they had no recent intelligence indicating such a plot was active.
The compound raid netted a man who had been on the run for nearly a decade after his terrorist organisation pulled off the devastating attacks of September 11, 2001. Even so, in the administration's haste to satisfy the world's hunger for details and eager to make the most of the moment, officials told a tale tarnished by discrepancies and apparent exaggeration.
Whether that matters to most Americans, gratified if not joyful that bin Laden is dead, is an open question. Republican House Speaker John Boehner, for one, shrugged off the backtracking to focus on the big picture: "I had a conversation with the president, and the president outlined to me the series of actions that occurred on Sunday evening. I have no doubt that Osama bin Laden is dead."
President Barack Obama's visit to New York's ground zero on Thursday was a sombre and understated event, and he avoided mentioning bin Laden by name. A day earlier, he said the government would not release images of bin Laden's body, a decision taken in part to avoid the perception that America was crowing about killing him.
"We don't need to spike the football," Obama said.
The senior defence official 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 briefed 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 Defence 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 on Wednesday 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 defence official told Pentagon reporters in a briefing.
White House counterterrorism 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, before the administration announced bin Laden actually was unarmed although there were weapons in his room.
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.
