ABBOTTABAD, Paki­stan >> Osama bin Laden was holed up in a two-story house 100 yards from a Paki­stani military academy when four helicopters carrying U.S. forces swooped in yesterday, killing the world’s most wanted man and leaving his final hiding place in flames, Paki­stani officials and a witness said.

They said bin Laden’s guards opened fire from the roof of the compound in the small northwestern town of Abbot­ta­bad, and one of the choppers crashed. However U.S. officials said no Americans were hurt in the operation. The sound of at least two explosions rocked Abbot­ta­bad as the fighting raged.

Abbottabad is home to three Paki­stani army regiments and thousands of military personnel and is dotted with military buildings. The discovery that bin Laden was living in an army town in Paki­stan raises pointed questions about how he managed to evade capture and even whether Paki­stan’s military and intelligence leadership knew of his whereabouts and sheltered him.

Critics have long accused elements of Paki­stan’s security establishment of protecting bin Laden, though Islamabad has always denied this. Army and government officials gave no formal comment today.

Most intelligence assessments believed bin Laden was holed up somewhere along the lawless border area between Paki­stan and Af­ghani­stan, possibly in a cave and sheltered by loyal tribesmen.

It was not known how long bin Laden had been in Abbot­ta­bad, which is less than half a day’s drive from the border region with Af­ghani­stan and two hours from the capital, Islamabad.

It was also unclear how much of a role — if any — Paki­stani security forces played in the operation. A Paki­stani official said the choppers took off from Ghazi air base in northwestern Paki­stan, where the U.S. army was based to help out in the aftermath of the floods in 2010.

Pakistani officials said a son of bin Laden and three other people were killed. Other unidentified males were taken by helicopter from the scene, while four children and two woman left in an ambulance, the official said.

Abbottabad resident Mohammad Ha­roon Ra­sheed said the raid happened at about 1:15 a.m. local time.

“I heard a thundering sound, followed by heavy firing. Then firing suddenly stopped. Then more thundering, then a big blast,” he said. “In the morning when we went out to see what happened, some helicopter wreckage was lying in an open field.”

He said the house was 100 yards away from the gate of the Kakul Military Academy, an army-run institution where top officers train.