Pakistan's prime minister said Monday that usama bin Laden's death in an American raid was "indeed justice done" and insisted the relationship with the U.S. was still strong. But he warned Washington that future unilateral strikes could be met with "full force."

Prime Minister Yousuf Raza Gilani also expressed confidence in Pakistan's military and Inter-Services Intelligence agency, which have been heavily criticized for failing to confront the U.S. Navy SEALs who conducted last week's helicopter raid without notifying Pakistan first.

The operation took place May 2 in Abbottabad, an army town only two and a half hour's drive outside the capital. The location of bin Laden's hide-out has sparked suspicion that Pakistani officials knew where the Al Qaeda leader was hiding and may have been helping him.

Gilani adamantly rejected those allegations, saying, "It is disingenuous for anyone to blame Pakistan or state institutions of Pakistan, including the ISI and the armed forces, for being in cahoots with Al Qaeda."

"Allegations of complicity or incompetence are absurd. Pakistan is not the birthplace of Al Qaeda," said Gilani in a speech to parliament. "We did not invite Usama bin Laden to Pakistan or even to Afghanistan."

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Gilani agreed that the failure to find bin Laden, who was reportedly living in Abbottabad for up to six years, was a mistake. But he insisted it wasn't Pakistan's alone.

"Yes, there has been an intelligence failure," said Gilani. "It is not only ours but of all the intelligence agencies of the world."

He said that the army will conduct an inquiry into the raid and military officials will brief parliament later in May.

The Pakistani military scrambled F-16 fighters and sent forces to bin Laden's compound as soon as they were aware of the raid, said Gilani. Even though they were unable to interdict U.S. forces before they were on their way back to Afghanistan, he expressed confidence in their performance.

"Our response demonstrates that our armed forces reacted, as was expected of them," said Gilani.

He warned the U.S. against launching future such attacks, saying "unilateralism runs the inherent risk of serious consequences."

"Pakistan reserves the right to retaliate with full force," said Gilani. "No one should underestimate the resolve and capability of our nation and armed forces to defend our sacred homeland."

But he insisted that relations with the U.S. remain strong and the two countries have worked well together during this period of crisis.

"Our communications at the official and diplomatic levels with the U.S., during this phase, have been good, productive and straight forward," said Gilani.

He also praised the result of the raid.

"Usama bin Laden was the most wanted terrorist and enemy number one of the civilized world," said Gilani. "Elimination of Usama bin Laden, who launched waves after waves of terrorists attacks against innocent Pakistanis, is indeed justice done."

On Sunday, Pakistan's ambassador to the United States vowed that "heads will roll" following an investigation into how bin Laden was able to hide out for years in a military city in northern Pakistan, as President Obama said the terror leader must have benefited from a "support network" inside Pakistan. 

The comments are the latest developments in the diplomatic dance both countries have been performing since the U.S. raid on bin Laden's compound last weekend. 

Top U.S. officials say they have serious questions for Pakistan's government and that an investigation is critical. Pakistani officials continue to criticize the Obama administration for crossing its borders for the raid without first telling Islamabad. 

But both sides have also sought to dial back tensions a hair. National Security Adviser Tom Donilon said Sunday there's no evidence so far to suggest Pakistani leaders were involved in sheltering bin Laden. And amid discussion on Capitol Hill about the possibility of cutting off billions in U.S. aid to Pakistan, the country's U.S. ambassador said the U.S. and Pakistan "need each other" and will continue to cooperate -- he sought to assure the U.S. his country is doing all it can to assist in the fight against Al Qaeda. 

Husain Haqqani, in an interview with ABC's "This Week," said that if anybody in the government, military or intelligence knew of bin Laden's whereabouts, "we would have taken action." 

"Usama bin Laden's presence in Pakistan was not to Pakistan's advantage," he said. "A lot more people have been arrested in Pakistan, including Al Qaeda people, than in any other country. So Pakistan did not have a policy of protecting these people." 

He vowed tough consequences if the investigation reveals any "complicity" inside the government. 

"Heads will roll once the investigation has been completed. Now, if those heads are rolled on account of incompetence, we will share that information with you. And if, God forbid, somebody's complicity is discovered, there will be zero tolerance for that, as well," Haqqani said, adding that bin Laden's wives and children who were living on the compound are being interrogated. "Pakistan wants to put to rest any, any misgivings the world has about our role." 

At the same time, the ambassador prodded the United States, suggesting U.S. focus on Iraq and Afghanistan distracted attention away from Pakistan, contributing to the "cracks through which things fell." 

Plus, he said, Pakistan was "offended" by the "violation of our sovereignty" allegedly inherent in the U.S. raid last weekend. 

The Associated Press contributed to this report.