Only one of four principal targets shot dead by US commandos in the raid which killed Osama bin Laden was involved in any hostile fire, a person familiar with the latest US government reporting on the raid told Reuters on Thursday.

The account of Monday's daring 40-minute raid has new descriptions of the event, including that Navy SEALs shot an occupant of the compound who they thought was armed, but apparently was not.

It confirms that bin Laden was not armed when he was shot dead, nor are there indications that he directly threatened his attackers, according to the first source and a second US government source who is familiar with briefings on the raid.

They requested anonymity because they were not authorized to speak for the record.

The Obama administration had given numerous, conflicting accounts of the raid this week, and it is possible these accounts will be revised yet again.

Here is a chronological version of what is now said to have happened on Monday when the SEAL team raided bin Laden's hide-out in Abbotabad, Pakistan:

A SEAL squad moved in darkness on the guest house, one of two dwellings inside the walls of bin Laden's compound. They were met with hostile fire. As they moved in, they shot a man who was in the guest house.

He turned out to be Abu Ahmed Al-Kuwaiti, the al Qaeda courier whose activities the CIA and other US intelligence agencies had been investigating for years and who they believed would lead them to bin Laden.

After shooting al-Kuwaiti, the two sources familiar with official accounts said, US commandos moved onto the compound's three-story main residence.

As they entered the house, they saw a man with his hands behind his back. Fearing that the man might be holding a weapon behind him, the commandos shot him dead.

It turned out that the man, who was the brother of Abu Ahmed al Kuwaiti and another suspected al Qaeda courier, was not holding a weapon, according to the two sources familiar with official accounts.

However, the attackers did subsequently find weapons near the second man's body, the sources said.

After killing the second courier, commandos started climbing the stairs to the house's upper floors. As they climbed, a man charged down the stairs at them, and was shot dead. US authorities now believe that he was Osama bin Laden's son.

As commandos proceeded up the stairs, the sources said, they saw a person they believed was bin Laden either poke his head out of a door or over a balcony. One of the sources said that the attackers took at least one shot at the person, who then retreated back inside the room he had come from.

The US commandos proceeded to the top floor and into the room where the man had retreated. While entering the room, they were rushed by a woman. The woman, now believed to be one of bin Laden's wives, was shot in the leg.

After shooting her, the commandos pushed her to the side. Precisely what bin Laden then did, and what his reaction was when the commandos entered and shot his wife, is unclear.

But the people familiar with official accounts said the attackers did not wait for much of a reaction, and almost immediately shot the al Qaeda leader dead.