A U.S. missile strike that killed a top Al Qaeda commander in Pakistan marked a significant victory for the U.S. in its battle against the terror network after a series of pessimistic assessments of the American-led campaign against the Taliban in neighboring Afghanistan.

The death of Abu Laith al-Libi was reported Thursday on Islamic extremist Web sites and confirmed by an American official, who said the veteran Al Qaeda leader died when a missile from a U.S. Predator drone struck a compound in Pakistan's North Waziristan region late Monday.

A Pakistan government spokesman in Islamabad said he had no information to prove al-Libi was killed in the strike, which occurred near the town of Mir Ali. But Pakistani intelligence officials in Miran Shah, a main town in North Waziristan, said there were strong indications he died.

"Our sources among militants ... are telling us that al-Libi died in the U.S. missile attack" along with about a dozen others, said a security official who asked not to be named because he was not authorized to speak to the media. A second intelligence official confirmed that account.

Two Pakistani intelligence officials said the missile was fired while al-Libi or some of his associates were using satellite phones and a computer at the house of Abdul Sattar, a local tribal leader known for his links to extremists.

Another official said in Islamabad that Sattar's home was only a mile from a base used by Pakistani security forces.

"Our sources have visited the area," the official said. "They have reported that Abdul Sattar's guest house was completely destroyed."

All the officials spoke on condition of anonymity because their information was sensitive.

The Predator is an unmanned reconnaissance aircraft that has been armed by both the U.S. Air Force and CIA with Hellfire anti-tank missiles. Even though all signs point to the CIA, agency officials would not confirm that their aircraft were involved in the strike.

Terrorism experts said al-Libi's death was a significant setback for Al Qeada because of his extensive ties to the Taliban, but they said the terror network would likely regroup and replace him.

The U.S. says al-Libi — whose name means "the Libyan" in Arabic — was likely behind a February 2007 bombing at the U.S. base at Bagram in Afghanistan during a visit by Vice President Dick Cheney. The attack killed 23 people but Cheney was deep inside the sprawling base and was not hurt.

Al-Libi's death was reported at a time of growing pessimism over the U.S.-led campaign against the resurgent Taliban across the border in Afghanistan.

An independent study co-chaired by retired Marine Corps Gen. James Jones and former U.N. Ambassador Thomas Pickering warned this week that Afghanistan risks becoming a failed state because of deteriorating international support and the growing Taliban insurgency.

The study concluded the United States risks losing the "forgotten war" in Afghanistan unless it re-energize anti-terrorism efforts in Afghanistan and Pakistan.

Among those who died in the missile strike were Arabs, Turkmen from central Asia and local Taliban members, according to an intelligence official in the area who spoke on condition of anonymity. He said the bodies of those killed were badly mangled by the force of the explosion and it was difficult to identify them.

In the past, coalition forces in Afghanistan are believed to have launched a number of similar missile strikes against Taliban and Al Qaeda militants hiding on the Pakistani side of the border, but the U.S. military has never confirmed any of them.

"We have no official information on this. Coalition forces do not conduct operations in Pakistan," Maj. Chris Belcher, a spokesman for the U.S.-led coalition troops in Afghanistan, said Friday.

Pakistan President Pervez Musharraf has repeatedly said he would not permit U.S. military action against al-Qaida members believed to be regrouping in the wild borderlands near Afghanistan. Musharraf has downplayed U.S. concerns about a significant al-Qaida presence inside Pakistan.

However, a former senior Pakistani intelligence officer familiar with the area said al-Libi was probably in North Waziristan to "give tasks" to local militants. The official, who spoke on condition of anonymity because of the sensitivity of the issue, said al-Libi was among the top five al-Qaida leaders with longtime contacts in North Waziristan.

"Al-Libi has been waging jihad for more than 10 years and it will be a blow to both Al Qaeda and the Taliban, but not in a way that will lead to the downfall of those organizations," said Eric Rosenbach, terror expert and executive director of the Center for International Affairs at Harvard's Kennedy School.

A senior U.S. official said last week that the top two U.S. intelligence officials made a secret visit to Pakistan in early January to seek permission from Musharraf for greater involvement of American forces in trying to ferret out Al Qaeda and other militant groups active in the tribal regions along the Afghanistan border.

The official, speaking on condition of anonymity given the secret nature of the talks, declined to disclose what was said, but Musharraf was quoted two days after the Jan. 9 meeting with CIA Director Michael Hayden and Mike McConnell, director of national intelligence, as saying U.S. troops would be regarded as invaders if they crossed into Pakistan to hunt Al Qaeda militants.

Al-Libi was among the most high-profile figures in Al Qaeda after its leader, Osama bin Laden, and his deputy Ayman al-Zawahri.

In spring 2007, al-Qaida's media wing, Al-Sahab, released a video interview with a bearded man identified as al-Libi. In it, he accuses Shiite Muslims of fighting alongside American forces in Iraq, and claimed that mujahedeen would crush foreign troops in Afghanistan.

A Pakistani intelligence official said al-Libi was based near Mir Ali until late 2003, when he moved back into Afghanistan to take charge of Al Qaeda operations on both sides of the border area. But he retained links with North Waziristan, the official said on condition of anonymity because of the sensitivity of the issue.