The Americans had a $200,000 bounty on his head. He tried to assassinate Vice President Cheney last year in Afghanistan, say US officials. But one of Al Qaeda's most senior commanders in Afghanistan, Abu Laith al-Libi, appears to be dead. He was killed in a US missile strike in a remote part of Pakistan this week, according to a radical Islamist website.
Still, his reported killing late Monday or early Tuesday just outside Mir Ali in north Waziristan represents a significant gain in American or coalition intelligence gathering within the restive tribal belt. As of Thursday, his death had not been officially confirmed.
"It means they are having some accurate intelligence information gathering.... Usually the second rank of leadership is very careful in its movements," says Abdel Bari Atwan, editor in chief of al-Quds al-Arabi newspaper in London and the author of "The Secret History of Al Qaeda."
Mr. Atwan says that after many reports of unsuccessful attempts at targeting senior Al Qaeda leadership in the region, "it seems this time they have accurate information, which is a success.
"It's a blow to [Al Qaeda], but not a crippling blow. Once you cut off one head, three or four or five more emerge. He will definitely be replaced."
Libi, from Libya, was an Al Qaeda training camp leader who has appeared in many videos on militant websites and whom the United States says was behind the February 2007 bombing at the Bagram Air Base in Afghanistan during a visit by the vice president that killed 23 people.
A Pakistani intelligence official said that Libi was based until late 2003 in the north Waziristan village of Norak, about five miles outside Mir Ali, where he had several compounds. He shifted inside Afghanistan after he took charge of Al Qaeda operations on both sides of the border, but retained links with Norak.
Martin Navias, an analyst with Britain's Center for Defence Studies, says that the US has often said it would step up operations in Pakistan, but he was uncertain that this latest strike was an expression of this more aggressive stance against Al Qaeda in the region.
"It's the kind of operation that reflects good intelligence.... It's significant in the propaganda sense for the Americans, but it is not going to have a major operational effect."
The Islamist militant website that announced his death said Libi "was martyred with a group of his brothers in the land of Muslim Pakistan.... Though we are sad for his loss, he left a legacy that will inflame the enemy nation and religion."
• Material from the Associated Press was used in this report.