(CNN) -- In the dark of night, U.S. helicopters approached a high-walled compound in Pakistan on a mission to capture or kill one of the world's most notorious terrorist leaders.
Less than 40 minutes later -- early Monday morning in Pakistan -- Osama bin Laden was dead, along with four others inside the complex, and the U.S. forces departed with the slain al Qaeda leader's body to fulfill a vow that originated shortly after the September 11, 2001, terrorist attacks on the United States.
Speaking from the White House Sunday night, U.S. President Barack Obama announced the successful raid. Senior administration officials provided further details on the assault on the compound they believe was built five years ago for the specific purpose of hiding bin Laden.
The compound is in Abbottabad, about 50 kilometers (31 miles) north of the Pakistani capital of Islamabad. The city sits in a mountainous region of Pakistan and is not heavily populated. Many of the residents are army personnel.
While senior administration officials would not offer a breakdown of the U.S. mission's composition, a senior defense official said U.S. Navy SEALs were involved.
After years of intelligence work and months of following a specific lead, they traced a courier linked to bin Laden to the compound in Abbottabad.
When first built, the compound was secluded and reachable by only a dirt road, the officials said. In recent years, more residences built up around it, but it remained by far the largest and most heavily secured property in the area, they said.
The mission ordered Friday by Obama encountered outer walls up to 18 feet tall topped with barbed wire, with two security gates and a series of internal walls that sectioned off different portions of the compound, the senior administration officials said. The main structure was a three-story building with few windows facing the outside of the compound, and a third-floor terrace had a seven-foot privacy wall, they said.
Months of intelligence work determined that the compound was custom-built to hide a high-value terrorism suspect, almost certainly bin Laden. The officials noted there was no telephone or Internet service at the dwelling, which was valued at more than $1 million, and its occupants burned their trash, rather than leave it out for collection like other area residents.
Calling the U.S. operation a surgical raid, officials said it was conducted by a small team and designed to minimize collateral damage. Upon landing, the team encountered resistance from bin Laden and three other men that resulted in a firefight.
In the end, all four of the combatants in the compound were dead, along with a woman whom one of the men used as a human shield, the officials said. Sources said bin Laden was shot in the head.
At some point, one of the assaulting helicopters crashed due to a mechanical failure, according to the officials. It was destroyed as the U.S. team flew away, they said.
Obama and the senior administration officials said no U.S. forces were harmed in the operation, which took place very early Monday morning Pakistan time.
U.S. officials said they used a number of methods to identify the body as bin Laden.
One official said it was clear to the assault force that the body matched bin Laden's description, but they used "facial recognition work, amongst other things, to confirm the identity."
A senior national security official told CNN that they had multiple confirmations that the body was bin Laden, saying they had the "ability to run images of the body and the face."
Another U.S. official told CNN that bin Laden has already been buried at sea. The official said his body was handled in the Islamic tradition, but did not elaborate.
A senior administration official also said bin Laden's body would be "handled in accordance with Islamic practice and tradition. This is something that we take very seriously, and so therefore this is being handled in an appropriate manner."
According to the senior administration officials, intelligence work determined at the beginning of 2011 that bin Laden might be located at the compound in Pakistan. By mid-February, the intelligence was considered strong enough to begin considering action pledged by Obama when bin Laden's whereabouts had been determined.
To discuss that intelligence and develop a plan, Obama chaired five National Security Council meetings from mid-March until late April, with the last two on April 19 and April 28 -- last Thursday. The next day, on Friday, Obama gave the order for the mission, the officials said.
The key break involved one of the few couriers trusted by bin Laden, according to the officials. About two years ago, intelligence work identified where the courier and his brother lived and operated in Pakistan, and it took until August of last year to find the compound in Abbottabad raided Sunday, they said.
"When we saw the compound where the brothers lived, we were shocked by what we saw -- an extraordinarily unique compound," one senior administration official said. "The compound sits on a large plot of land in an area that was relatively secluded when it was built. It is roughly eight times larger than the other homes in the area."
Noting that the courier and his brother had no discernible source of wealth to live at such a property, intelligence analysts concluded the compound was "custom-built to hide someone of extraordinary significance," the official said, adding: "Everything was consistent with what experts thought Osama bin Laden's compound would look like."
Another senior administration official told reporters that Obama's administration did not share intelligence gathered beforehand with any other country -- including Pakistan -- for security reasons. The official said that only a small group of people inside the U.S government knew about this operation in advance.