ISLAMABAD, Pakistan -- Counterterrorism officials say a growing rift between Arab members of al Qaeda and their Central Asian allies is tearing at the network of Islamic extremists.
The rivalry might have contributed to the arrest this month of one of Osama bin Laden's top lieutenants, a Libyan described as al Qaeda's No. 3 man and known to have had differences with Uzbeks.
Captured Uzbek, Chechen and Tajik suspects have been giving up information about the movements of Arab al Qaeda militants in recent months, four Pakistani intelligence agents said, leading to a series of successful raids and arrests.
"When push comes to shove, the Uzbeks are going to stick together, and the Arabs are going to stick together," said Kenneth Katzman, a terrorism analyst with the Congressional Research Service in Washington. "I think the Uzbek guerrillas have had no home. Some of this could be a battle for survival."
An agent in Pakistan's Inter-Services Intelligence, the country's equivalent of the CIA, said tensions with the Central Asians began building in late 2001, when hundreds of Arab al Qaeda militants poured across the Afghan border into the Pakistani tribal areas of South and North Waziristan.
Hundreds of Central Asians who had fought alongside the Taliban fled across the border, too, joining countrymen who had settled in Waziristan during the Afghan war against the Soviets in the 1980s.
At the time, the al Qaeda-linked Islamic Movement of Uzbekistan, whose fighters also were hiding in the area, was left rudderless. Its commander and co-founder, Juma Namangani, reportedly was killed in a U.S. bombing campaign in late 2001.
He was replaced by Tahir Yuldash, known as a political philosopher rather than a military leader, said Mr. Katzman of the Congressional Research Service.
"They didn't have a strong figure anymore to articulate their interests," said Mr. Katzman, whose agency advises U.S. lawmakers. "They had to rely more on the Arab leaders of al Qaeda."
The heat began to rise amid a Pakistani military crackdown that flushed many militants out of the region in 2003 and 2004.
The Uzbeks and other Central Asians found themselves competing with Arab members of al Qaeda for hide-outs and resources, with Arabs having the political and economic advantage, Mr. Katzman said.
Adding to the tensions was the senior al Qaeda figures' lack of trust in the Central Asian fighters, said a senior Pakistani Interior Ministry official.
Increasingly, the two sides began operating independently, often competing for the same money, weapons and support of the Pakistani tribesmen. Captured Uzbek, Chechen and Tajik fighters felt far more loyalty to Yuldash than to the Arab al Qaeda men.
A Pakistani intelligence official said it was difficult to get captured Uzbeks to talk about Yuldash, "but it was a lot easier to grill them for clues about the Arabs and their possible hide-outs. They felt far less loyalty."