The U.S. ambassador to Pakistan, Ryan Crocker, says he no longer believes Osama bin Laden is in operational control of the al-Qaida terrorist network.
Speaking to reporters in Islamabad, Mr. Crocker said he believed al-Qaida is, in his words, "in serious trouble."
He claimed bin Laden, thought to be hiding out in the rugged border area dividing Pakistan and Afghanistan, is too isolated to maintain contact with al-Qaida cells around the world.
Mr. Crocker did not say whether his remarks were based on new intelligence.
The ambassador's comments come just days after an internet video showed al-Qaida deputy commander Ayman al-Zawahiri claiming bin Laden was still directing the terrorist group's global network.
The undated video interview is believed to be several-months old.
Al-Qaida experts say most available evidence suggests Zawahiri, and not bin Laden, is running al-Qaida's operations.
Raheem-Ullah Yousefzai, in Pakistan, is one of the few analysts who has interviewed both men since the 2001 terrorist attacks in the United States. He says since late 2001, Zawahiri has apparently assumed day-to-day control of al-Qaida.
"He is the brains, the organizer of al-Qaida," said Raheem-Ullah Yousefzai. "He may not be a military man, but he is very skilled in organizational work."
The last time Osama bin Laden was seen in a video was in 2004, just before the U.S. presidential election.
Since then thousands of Pakistani troops deployed along the border with Afghanistan have conducted a series of major counter-terror operations.
Pakistan President Pervez Musharraf has repeatedly claimed al-Qaida's local bases and communications network have been destroyed, while hundreds of militants have been captured or killed.