Angry US policymakers on Monday demanded that Pakistan explain how Osama bin Laden, the man blamed for killing up to 3,000 Americans, managed to live unperturbed in a country receiving billions of US aid.
But President Barack Obama stopped short of questioning the partnership with Pakistan, with analysts saying the administration saw little gain from further stirring tensions and potentially losing US access in the frontline nation.
US lawmakers expressed amazement that the world's most wanted man could have resided -- apparently for years -- in a comfortable home in Abbottabad, a hillside retreat close to Islamabad popular with retired Pakistani generals.
In a city home to an elite military academy, bin Laden lived in a custom-built three-story villa that dwarfed other homes and had towering walls with barbed wire.
"It's been there for five years. It's kind of hard to imagine that the military at least did not have an idea of what was going on inside," said Senator Carl Levin, chair of the Armed Services Committee.
Senator Joe Lieberman, the chair of the Homeland Security Committee, predicted "real pressure" on Islamabad and said that Pakistan will need to "prove to us that they didn't know that bin Laden was there."
The Obama administration last year said it would seek another $2 billion for Pakistan's military, on top of a five-year, $7.5 billion civilian package approved in 2009 aimed at weakening the allure of Islamic extremists.
Senator Susan Collins, the top Republican on the Homeland Security Committee, called for "more strings attached" to military assistance after bin Laden's capture.
"I think that this tells us once again that, unfortunately, Pakistan at times is playing a double game and that is very troubling to me," she said.
John Brennan, Obama's top counter-terrorism adviser, said that the United States was in talks with Pakistan about how the most-wanted fugitive was able to live in Abbottabad.
"It is inconceivable that bin Laden did not have a support system in the country to allow him to stay there for an extended period of time," Brennan told reporters.
But the Obama administration carefully avoided criticizing ties with Pakistan. Announcing bin Laden's death late Sunday, Obama said that "our counter-terrorism cooperation with Pakistan helped lead us to bin Laden."
The Obama administration has put a top priority on bolstering President Asif Ali Zardari's civilian government through development aid, while also keeping ties to the traditional power-brokers in the army and intelligence service.
Secretary of State Hillary Clinton said Monday that bin Laden had also "declared war on Pakistan" through violence that has killed civilians.
"In Pakistan, we are committed to supporting the people and government as they defend their own democracy from violent extremism," she told reporters.
Analysts said the Obama administration saw no advantage in publicly chastising Pakistan as the United States needed to maintain access to the country as its decade-long war in Afghanistan moves to a denouement.
Besides, experts said, the bin Laden case speaks for itself.
"What this does is strengthen the Obama administration's hand in Pakistan," said Lisa Curtis, a senior research fellow at the Heritage Foundation, a conservative think-tank.
"It finally puts to rest all the statements that various people have been making in Pakistan that Osama bin Laden was not in Pakistan and that this was all a Western conspiracy theory," she said.
"If you see Pakistan digging in its heels and talking about violations of Pakistani sovereignty, I think then you can expect a severe deterioration in relations," she said.
Relations between Washington and Islamabad have long been rocky. Pakistan has protested US drone attacks against suspected extremists on its territory -- mostly in lawless tribal areas and not near Islamabad -- and tensions soared this year when a CIA agent with diplomatic immunity gunned down two Pakistanis.
Pakistan helped create Afghanistan's Taliban regime. Then military ruler Pervez Musharraf switched sides overnight following the September 11, 2001 attacks, but the United States remains unpopular with most of the public.
Shuja Nawaz, director of the South Asia Center at the Atlantic Council, said that both the United States and Pakistan had reason to keep cooperation, despite the difficult questions raised over bin Laden.
"Pakistan needs support to continue the fight internally and the United States needs Pakistan's assistance in transforming from a purely military access to reconciliation or some other orderly exit from Afghanistan," he said.
"The common interests don't change and Pakistan's strategic location won't change," he said.