Reports of the operation to find al-Qaeda leader Osama Bin Laden paint a picture of high tension, with White House officials watching the operation unfold on a live video feed.
At the climax, at the end of a 40-minute firefight, one of the soldiers uttered the words: "Geronimo EKIA" - meaning a man visually identified by a code word for Bin Laden had been killed in action, officials said.
A high-risk operation given the green light by President Barack Obama in what his counter-terrorism adviser, John Brennan, termed "one of the gutsiest calls by any president in recent memory" had achieved its aim, the death of Washington's most wanted man.
Both US and Pakistani officials assert Pakistan was kept completely in the dark about the operation and reports suggest the tension lingered as the team led by US Navy Seals made a high-speed dash to Afghanistan at the end of it.
A suspicious Pakistani air force started scrambling jets, Mr Brennan said, leading to last-minute worries the US team could still be in danger.
Explosions The operation took place at a fortified compound on the outskirts of Abbottabad in north-west Pakistan.
It happened at some time between 0000 and 0130 local time on Monday morning (1900-2030 GMT on Sunday), dozens of local residents told a BBC reporter. The two US helicopters were seen flying low over the area, causing panic among some residents.
Residents describe hearing three explosions several minutes apart, followed by a huge explosion that shook their houses and knocked crockery from shelves. Most residents said they then also heard gunshots, but that the firing was brief, just a couple of minutes or so.
As the explosions started, they say, the lights in the area went off, going on and off again shortly afterwards. One report quotes some residents as saying they were commanded in Pashto - not the common language of the area - to turn their lights off, but this is unconfirmed.
It is believed that people inside the house fired at the helicopters, but eventually they were able to land or hover outside the compound, and the US commandos emerged from them.
US officials said that at some point in the operation one of the two helicopters developed a technical fault - witnesses said it might have been hit by gunfire from the ground. Rather than let it fall into the wrong hands, the commandos blew it up.
One report of the operation emerged in real-time: Sohaib Athar, an IT consultant living in Abbottabad, posted on Twitter at about 0100 (2100 GMT) that a helicopter was hovering above the city.
e continued tweeting as the operation unfolded before eventually realising: "Uh oh, now I'm the guy who liveblogged the Osama raid without knowing it."
There are contradictory reports about which base the helicopters took off from, with some saying the US air bases at Jalalabad or Bagram in Afghanistan, but others suggesting it was the nearby Ghazi air base inside Pakistan.
Security concerns The target of the operation was the compound, which had at its centre a large three-storey building with 12ft high concrete high walls, barbed wire and CCTV cameras - and few windows.
The compound - valued at about $1m (£600,000) - had two security gates but no phone or internet lines running into the building.
Its occupants were so concerned about security that they were reported to burn their rubbish rather than leave it out for collection as other residents in the area did.
Mr Brennan told reporters that the commando team had been "able and prepared" to take Bin Laden alive "if he didn't present any threat".
"The concern was that Bin Laden would oppose any type of capture operation. Indeed, he did. It was a firefight. He, therefore, was killed in that firefight, and that's when the remains were removed," said Mr Brennan.
White House spokesman Jay Carney said on Tuesday Bin Laden was unarmed when he was killed, but that he did resist capture.
The al-Qaeda leader was in his bedroom when he was shot twice, officials said - once in the head and once in the chest.
Footage purporting to be of the bedroom appears to show a round gaping hole in the wall, suggesting US forces blasted their way into the building.
US officials described the operation as a "surgical raid" and said that as well as Bin Laden, three adult males - thought to comprise Bin Laden's trusted courier, his brother and Bin Laden's adult son, Khaled - were killed.
A woman was also killed in crossfire on the first floor of the building. There were conflicting reports as to whether the woman who died was being used as a human shield.
One of Bin Laden's wives - believed to be his fourth wife, Amal al-Ahmed Sadah from Yemen - was shot in the leg when she "rushed" one of the US commandos when he entered the room the al-Qaeda leader was in, Mr Carney said.
A senior intelligence official told reporters at a US Department of Defense briefing that Bin Laden's body was identified visually on the scene by operatives, by name by a woman at the scene believed to be his wife, by CIA specialists using photos and finally later on Monday by experts who found "virtually a 100% DNA match of the body against DNA of several Bin Laden family members".
The team left the compound carrying documents, hard drives and DVDs which it is hoped could yield further valuable intelligence data, officials said.
According to an official from Pakistan's main intelligence agency, the ISI, there were 17 or 18 people in the compound at the time of the attack, while US officials say those who survived the attack included one of Bin Laden's wives and a daughter, and eight to nine other children who were not apparently Bin Laden's.
The ISI and US officials contradict each other as to whether a detainee was taken away alive.
Bin Laden's body was flown to Afghanistan and later to the US aircraft carrier, the Carl Vinson, in the north Arabian Sea.
Mr Carney said the body was prepared for burial "in conformance with Islamic precepts and practice", then placed in a weighted bag and dropped into the water from the vessel's deck. Officials said this was to avoid his grave becoming a shrine.
'Trusted' courier The compound is in a residential district of Abbottabad's suburbs called Bilal Town, which is home to a number of retired military officers from the area.
The compound is just 1km from the Pakistan Military Academy, an elite military training centre which is being described as Pakistan's equivalent to Britain's Sandhurst or the West Point academy in the US.
Pakistan's army chief is a regular visitor to the academy, where he attends graduation parades, and it is likely the area would have had a constant and significant military presence and checkpoints.
As details of the raid emerged it became clear that the operation had been long in the planning. US officials said they had received intelligence that Bin Laden might be in that compound as long ago as last summer.
CIA experts found significant circumstantial evidence that the "high value target" living at the compound was Bin Laden, but US satellites were not able to photograph Bin Laden or any members of his family. In the end, they were only 60-80% confident that the al-Qaeda leader was there.
US intelligence agents focussed in particular on one of Bin Laden's couriers - a man identified as a protege of captured al-Qaeda commander Khalid Sheikh Mohammed.
The Kuwait-born courier's nom de guerre - Abu Ahmed al-Kuwaiti - was reportedly given to US interrogators by detainees at Guantanamo Bay in Cuba, US media reported. It took years of work to identify his true name, Sheikh Abu Ahmed.
He appeared to be one of the few couriers completely trusted by Bin Laden, who helped keep the al-Qaeda figurehead in touch with the rest of the world.
In July, Pakistani agents working for the CIA spotted him driving a vehicle near the northern city of Peshawar. After weeks of surveillance, in August he led them to the sprawling compound in Abbottabad.
The order to carry out the mission was finally given by President Obama last Friday, after he had held five National Security Council meetings in March and April.
The director of the CIA, Leon Panetta, said during one meeting: "We have the best evidence since [the 2001 battle of] Tora Bora, and that then makes it clear that we have an obligation to act."
Mr Panetta said Mr Obama ruled out a high-altitude bombing raid by a B-2 bombers, or cruise-missile strike because of the possibility of too much collateral damage. There was also a concern that such options might obliterate evidence of Bin Laden's death , as well as cause big diplomatic fallout if he was found not to be in the compound.
Instead, a helicopter assault emerged as the favoured option and the Navy Seals began rehearsing at training facilities on both US coasts, where replicas of the compound were built. They were not told who their target might be until later.
Mr Panetta said the Pakistani government was also not informed of the operation in advance because the CIA feared that word of it might have been leaked.
"It was decided that any effort to work with the Pakistanis could jeopardise the mission. They might alert the targets," he told Time magazine.
CIA officials turned a windowless seventh-floor conference room at Langley into a command centre for the operation, from where Mr Panetta passed on details to the president and his advisers in the White House.
"We have a visual on Geronimo," Mr Panetta said after troops entered the compound, according to the New York Times.
Minutes later, he told them: "Geronimo EKIA [Enemy Killed In Action]."
President Obama added: "We got him."
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