The United States has no "definitive evidence" that Pakistan knew Osama bin Laden had been living in the compound where a Navy SEALs assault team killed him, but the Pakistanis must now show convincingly their commitment to defeating the al-Qaida terrorist network, a senior Pentagon official said Thursday.
Meanwhile, Secretary of State Hillary Clinton warned that while the world's most-wanted terrorist had been killed, the threat from al-Qaida and other militant groups remained strong.
Michele Flournoy, the top policy aide to Defense Secretary Robert Gates, told reporters that the Pakistani government should, for example, help the U.S. exploit the materials the SEALs collected inside bin Laden's lair during their raid on Monday.
Flournoy was the first Pentagon official to comment on-the-record about the raid. She offered no new details about it, but said it dealt "a very severe blow" to al-Qaida and offers incentive for Pakistan to cooperate more fully in defeating the terrorist network.
"This is a real moment of opportunity for us in terms of making further gains against al-Qaida," she said.
Questions about whether Pakistan knew of bin Laden's whereabouts, and may even have helped hide him, arose immediately after Monday's raid. Flournoy said U.S. officials have pressed Pakistan for more details about the matter.
"We are still talking with the Pakistanis and trying to understand what they did know, what they didn't know," she said. "We do not have any definitive evidence at this point that they did know that Osama bin Laden was at this compound."
In Islamabad, Pakistan's army on Thursday called for cuts in the number of American military personnel inside the country to protest the raid, and it threatened to cut cooperation with Washington if it stages more unilateral raids on its territory. A small number of U.S. soldiers have been training Pakistani forces in counter-insurgency operations.
Flournoy, the undersecretary of defense for policy, said she held previously scheduled talks at the Pentagon on Monday, just hours after the raid was announced, with a Pakistani government delegation. In that session and follow-up talks on Tuesday, Flournoy said she made clear that members of Congress — even those who have been supporters of increased cooperation with Pakistan — will be increasingly skeptical about the wisdom of continuing to provide billions of dollars in U.S. aid.
Pakistan must take "very concrete and visible steps to show their cooperation as a counterterrorism partner," she said, "because I do think that Congress will have to be convinced to sustain both civilian and military assistance to Pakistan." She added that the Obama administration still intends to keep close ties to Pakistan, even as it presses the Pakistanis for more information about bin Laden's presence in Abbottabad, the military garrison town a few dozen miles from Islamabad, the capital.
In a letter to Clinton, Rep. Kay Granger, a Republican and chairwoman of the House Appropriations subcommittee on foreign operations, called for suspending direct government-to-government assistance to Pakistan.
"My opposition to the program has only been heightened by the discovery of the most notorious terrorist in the world living hundreds of yards from a Pakistani military installation for more than five years. This reinforces my greater concern that the government may be incapable of distributing U.S. funds in a transparent manner that allows proper oversight of taxpayer dollars," Granger wrote.
Sen. Richard Lugar, a Republican and a supporter of U.S. aid to Pakistan, said Thursday it would be self-defeating to walk away from the relationship.
"Distancing ourselves from Pakistan would be unwise and extremely dangerous," he told a Senate Foreign Relations Committee hearing. "It would weaken our intelligence gathering, limit our ability to prevent conflict between India and Pakistan, further complicate military operations in Afghanistan, end cooperation on finding terrorists, and eliminate engagement with Islamabad on the security of its nuclear weapons."
House Speaker John Boehner, R-Ohio, took the same view.
"It's not a time to back away from Pakistan," he said. "Frankly, I believe that our aid should continue to Pakistan."
Arrest in AbbottabadPakistani officials are pointing to the January arrest — in Abbottabad — of a man on the FBI's Most Wanted Terrorist list as an example of how they've been loyal partners in the war on terror.
Umar Patek, 40, is suspected of being one of the masterminds of Bali Bombings in 2002 that killed more than 200 people, including seven Americans. Patek's arrest was kept quiet until late March. The U.S. had offered a $1 milliion reward for Patek's arrest.
However, U.S. officials firmly denied a claim by Pakistani officials that Patek had provided any evidence that led them to the Bin Laden compound, also in Abbottabad.
"He had nothing to do with this," said an official, referring to the assault on the Bin Laden compound. "You have to understand, the Pakistanis are very embarrassed and looking to take credit whereever they can."
Flournoy predicted that any doubts about bin Laden's death will be erased, even without the U.S. releasing a photo of his corpse.
"In time it will become apparent -- undeniably apparent. I think al-Qaida will recognize that this is in fact the truth (and) and that they will make changes in their own leadership to reflect that truth," she said. "The same people who doubt whether he's dead today would probably look at a photo and doubt whether that's real."
During a meeting of foreign ministers in Rome to discuss the situation in Libya, Clinton said bin Laden's death "sent an unmistakable message about the strength and the resolve of the international community to stand against extremism and those who perpetuate it."
"Let us not forget that the battle to stop al-Qaida and its affiliates does not end with one death," she said. "We have to renew our resolve and redouble our efforts, not only in Afghanistan and Pakistan but around the world.
The possible was underlined by a story in Britain's The Sun newspaper on Thursday.
The newspaper said it contacted al-Qaida in the Arabian Peninsula, or AQAP — which is led by Anwar al-Awlaki, a U.S.-born cleric based in Yemen — posing as Britons seeking guidance on how to carry out the goals of the terror group in the U.K. Al-Awlaki has been tipped as al-Qaida's new leader.
"The options that you have for operations could be pipe bombs, assassinations or using a firearm at a location crowded with enemies," the reply said, according to The Sun.
The newspaper said the message was signed "Your brothers at al-Qaida of the Arabian Peninsula" and took several weeks to reach its account.
Emulating Mumbai?The recommended approach outlined in The Sun article called on potential al-Qaida recruits to emulate the militant operation carried out in Mumbai in 2008, in which gunmen besieged the Indian city and killed 166 people, including six Americans.
In 2010, top U.S. counterterrorism officials , noting that al-Qaida and those inspired by it were looking to the new approach to both carry out attacks more quickly and help them stay under the radar by keeping the plans on a smaller scale.
The email The Sun said it received also advised the undercover advice-seeker to work alone unless there was a "group of brothers" who could trust each other.
"We would also suggest that if you have decided to go ahead do not contact us because this may bring surveillance on you," the newspaper quoted the email as saying.
"However, right before you start your operation you may send us a message informing us of the operation without mentioning the details. This is of course if you want us to sponsor the operation," the email reportedly continued.
Though bin Laden's deputy, Ayman al-Zawahiri, would now be the top-ranking leader in al-Qaida, a senior U.S. official told NBC News that .
The organization could instead look to a figure like al-Awlaki. U.S. investigators have found that he communicated with the army major who allegedly went on a 2009 shooting spree at Fort Hood in Texas and that he instructed the Nigerian man suspected of trying to blow up a U.S. airliner on Christmas Day of that year.
Small, cheap attacksAwlaki has been an influential propagandist among English-speaking militants due to his prolific output of audio and video talks. The Obama administration in 2010 authorized the CIA to capture or kill him.
AQAP, formed from the 2009 merger of the group's Yemeni and Saudi wings, has vowed to bleed U.S. resources with small, cheap attacks that force the West to spend billions of dollars to guard against.
Underscoring the threat posed by the group's operation in Yemen, the country's defense ministry announced that two mid-level al-Qaida leaders were killed there Thursday.
The Yemeni defense ministry identified the men as two brothers, Musa'id and Abdullah Mubarak, and said they were killed at around dawn in the remote province of Shabwa, where a Yemen-based wing of al-Qaida is active.
It was not yet clear who carried out the attack and why they were targeted, but some nearby residents said they saw a drone in the air at the time of the killing while others reported seeing a rocket followed by an explosion on the ground.
Yemen, a U.S. ally against al-Qaida, declared open war on AQAP in January 2010, stepping up airstrikes in which civilians as well as militants were killed.
A U.S. diplomatic cable leaked in November said the United States was carrying out air raids on al-Qaida targets in Yemen, and that President Ali Abdullah Saleh agreed to conceal this from the public.
Saleh is an important U.S. ally but faces violent protests demanding his removal.
The conflict has put CIA and military counterterrorism operations on ice, officials said, leading to fears that the increasingly sophisticated terrorist group will grow even stronger.