A senior al-Qaeda leader, considered by US officials to be the group's second-in-command, was the target of a deadly US drone attack in Pakistan's North Waziristan on Monday, according to US and Pakistani sources.
US government sources said on Monday that they were unable to confirm whether Abu Yahya al-Libi had indeed had been killed in the airstrike. He is regarded as a very senior aide to al-Qaeda leader Ayman al-Zawahiri.
The drone raid that targeted al-Libi killed 15 people, according to Pakistani officials, who said more than half of the victims were "foreigners," most of them Arabs.
It was the third drone attack in as many days in Pakistan's tribal regions; a bombing on Saturday killed four people, and another on Sunday killed ten.
It is difficult to independently confirm the reports of al-Libi's death. Fighters in the region have already denied that he was killed.
A commander in North Waziristan closely associated with foreign fighters, however, said that al-Libi was alive.
"He has not been killed. This is not the first time claims have been made about his death. The Americans are suffering heavy losses in Afghanistan so they have resorted to making false claims," he told Reuters news agency.
Another local Taliban commander said the attack killed al-Libi's bodyguard and his driver, but not the al-Qaeda commander himself, according to the Associated Press news agency.
The Pakistani foreign ministry summoned Richard Hoagland, the US charge d'affaires in Islamabad, to protest the "government's serious concern regarding drone strikes in Pakistani territory."
Al-Libi, a Libyan native, reportedly travelled to Afghanistan in the 1990s.
He was captured in 2002 and detained at Bagram airbase in Afghanistan. But he escaped in 2005, along with three other detainees, and was never recaptured. He is the only one of the four still at large; the rest have either been captured or killed.
Al-Libi was elevated to al-Qaeda's number-two position last year, after the US raid in Pakistan which killed Osama bin Laden. He is not considered a skilled military commander; his value to the group is mostly as a propagandist. He appears frequently in the group's recruitment videos.
This is not the first time the US has reported him dead: al-Libi was initially believed to be the target of a drone strike in December 2009, but the actual victim was Saleh al-Somali, dubbed al-Qaeda's "external operations" chief.
If these reports are true, al-Libi would be the latest of more than a dozen high-ranking al-Qaeda commanders killed during the past year. The US state department had set a $1m reward for information leading to al-Libi.