The Al Qaeda-linked leader of the Islamic Movement of Uzbekistan is believed to have been killed by a U.S. missile strike in Pakistan's northwest, intelligence officials said Friday. The Taliban denied the claim.

Tahir Yuldash's death would be a significant blow to the militant groups that have wreaked havoc along the Afghan-Pakistan border and the latest victory for the covert American missile program.

Yuldash was wounded in an Aug. 27 missile strike in the South Waziristan tribal region and is believed to have died a few days later, said the four intelligence officials, who spoke on condition of anonymity because they were not authorized to talk to the media.

Many Uzbek militants hide in Pakistan's tribal regions and are involved in militancy there and in Afghanistan. The Uzbeks are considered some of the fiercest insurgents.

The Pakistani officials said they had received the information about Yuldash's death from militant sources. However, Qari Hussain, a top militant among the Taliban ranks, called The Associated Press on Friday to insist that Yuldash was not dead.

"These reports are all fake," Hussain said from an undisclosed location. "He is alive."

Independent confirmation of Yuldash's death is nearly impossible to obtain. South Waziristan is a major Al Qaeda and Taliban stronghold in Pakistan's tribal belt, and access is severely restricted as well as dangerous.

In addition, there are increasing reports that the military plans to wage a major offensive in South Waziristan in the coming days. Reports in Dawn, a major Pakistani newspaper, and The New York Times described the plans in Friday editions.

Pakistani military officials could not immediately be reached to confirm the reports.

The U.S. has launched scores of missiles against militant targets in Pakistan's tribal regions, and American officials say the program has killed several top militants. In August, a missile strike killed Baitullah Mehsud, Pakistan's Taliban chief.

The Taliban at first denied Mehsud had been hit, then confirmed his death more than two weeks later, insisting he had not died immediately.