Exiled Saudi dissident Osama Bin Laden is seen in this April 1998 picture in Afghanistan. Image Credit: AP

Washington: US special forces set out to kill Osama Bin Laden and dump his body in the sea to make it harder for the Al Qaida founder to become a martyr, US national security officials told Reuters on Monday.

"This was a kill operation," one of the officials said.

"If he had waved a white flag of surrender, he would have been taken alive," the official added. But the operating assumption among the US raiders, he added, was that Bin Laden would put up a fight - which he did.

Bin Laden "participated" in a firefight between the US commandos and residents of the fortified compound near the Pakistani capital Islamabad where he had been hiding, the official said.

Other US officials said the U.S. strike team shot the Al Qaida leader dead with bullets to the chest and head during the course of the 40-minute operation. He did not return fire.

Within hours of Bin Laden's death, which Obama announced in a dramatic, late-night White House speech, the commandos had buried bin Laden's body at sea, two US officials said.

It was done so that Bin Laden's body would not become a symbol of veneration or inspiration for would-be militants, US officials said.

"You wouldn't want to leave him so that his body could become a shrine," one of the officials said.

Three other men and a woman lay dead after the raid, but no Americans were killed. Bin Laden's wife, originally thought killed, was only wounded.

The woman killed in the raid was not used as a human shield by the Al Qaida leader before his death, a US official said, correcting an earlier description.

The operation was carried out by a team of about 15 special forces operatives - most, if not all, US Navy SEALs, according to US officials familiar with the details. They indicated the team was based in Afghanistan.

Forensic specialists

One official said it included forensic specialists whose job was to collect evidence proving that Bin Laden was caught in the raid and intelligence that might be useful in tracking down other Al Qaida leaders or foiling ongoing plots.

CIA 'was confident'

U.S. officials said the key information that eventually led to bin Laden's trail came from questioning of militants detained by US forces following the September 11, 2001, attacks on New York and Washington.

Captured militants, including some held at the US military prison at Guantanamo Bay in Cuba, told intelligence officials of a particular Al Qaida "courier" whom they had heard was close to Bin Laden.