Pakistan declared the killing of Osama bin Laden a "major setback" to global terrorism but it will inevitably come under pressure to explain how the al Qaeda leader was holed up in a mansion near a military facility.
Bin Laden was killed in a dramatic night-time raid by US helicopters and troops on his hideout in Abbottabad, a town that is home to a military academy and less then two hours' drive from the Pakistani capital, Islamabad.
"Osama bin Laden's death illustrates the resolve of the international community, including Pakistan, to fight and eliminate terrorism," the government said in a statement. "It constitutes a major setback to terrorist organisations around the world."
However, it was not clear whether the Pakistan military was involved in the operation and there was no official comment from the government for several hours after the news of bin Laden's killing broke, raising the possibility that Islamabad was taken by surprise.
That bin Laden, mastermind of the Sept. 11, 2001, attacks on the United States, was not hiding in mountains along the border but in relative comfort near a military academy will bolster those who have long argued that Pakistan has been playing a duplicitous hand.
Just 10 days ago Pakistan's army chief addressed army cadets at that very academy, saying the country's military had broken the back of militants linked to al Qaeda and the Taliban.
Washington has in the past accused Pakistan of maintaining ties to militants targeting US troops in neighbouring Afghanistan. Relations have soured in recent months over US drone attacks and CIA activities in the country.
Pakistan's powerful intelligence agency, the ISI, has long been suspected of links to al Qaeda's precursor, the Haqqani network, cultivated during the 1980s when Jalaluddin Haqqani was a feared battlefield commander against the Soviet Union in Afghanistan.
Pakistan's arch-rival, India, was quick to comment, saying the news underlined its "concern that terrorists belonging to different organisations find sanctuary in Pakistan".
"For some time there will be a lot of tension between Washington and Islamabad because bin Laden seems to have been living here close to Islamabad," said Imtiaz Gul, a Pakistani security analyst.
"If the ISI had known, then somebody within the ISI must have leaked this information," Gul said. "Pakistan will have to do a lot of damage control because the Americans have been reporting he is in Pakistan ... this is a serious blow to the credibility of Pakistan."
FLAMES, GUNSHOTS, A BLAST
Abbottabad is a popular summer resort, located in a valley surrounded by green hills near Pakistani Kashmir. Islamist militants, particularly those fighting in Indian-controlled Kashmir, used to have training camps near the town.
A Reuters reporter in the town on Monday said bin Laden's single-storey residence stood fourth in a row of about a dozen houses, a satellite perched on the roof above a walled compound. A helicopter covered by a sheet sat in a nearby field.
Mohammad Idrees, who lives around 400 meters from the house, said local residents were woken in the night by the sound of a big explosion. "We rushed to the rooftop and saw flames near that house. We also heard some gunshots," Idrees said. "Soon after the blast, we saw military vehicles rushing to the site of the blast."
Another resident, Nasir Khan, said that commandos had encircled the compound as three helicopters hovered overhead. "All of a sudden there was firing towards the helicopters from the ground," said Khan, who had watched the drama unfold from his rooftop. "There was intense firing and then I saw one of the helicopters crash."
A Pakistani military helicopter crashed near Abbottabad on Sunday night, killing one and wounding two, according to local media. It was unclear if the crash was related to bin Laden's death, but witnesses reported gunshots and heavy firing before one of two low-flying helicopters crashed near the academy.
Sohaib Athar, whose profile says he is an IT consultant taking a break from the ratrace by hiding in the mountains, sent out a stream of live updates on Twitter about the movement of helicopters and blasts without realising it was a raid on the world's most hunted man.
Some of his early tweets were: "Helicopter hovering above Abbottabad at 1 am (rare event); Go away helicopter - before I take out my giant swatter."
Then he reported his window rattling and a bang. "I hope it's not the start of something nasty," he tweeted. Soon after there were blasts. There were two helicopters, one of them had gone down, Athar wrote.
When he learnt it was bin Laden killed in Abbottabad, he tweeted: "ISI has confirmed it << Uh oh, there goes the neighborhood."