Reporting from Washington — A growing number of Taliban militants in the Pakistani border region are refusing to collaborate with Al Qaeda fighters, declining to provide shelter or assist in attacks in Afghanistan even in return for payment, according to U.S. military and counter-terrorism officials.
The officials, citing evidence from interrogation of detainees, communications intercepts and public statements on extremist websites, say that threats to the militants' long-term survival from Pakistani, Afghan and foreign military action are driving some Afghan Taliban away from Al Qaeda.
As a result, Al Qaeda fighters are in some cases being excluded from villages and other areas near the Afghanistan-Pakistan border where they once received sanctuary.
Al Qaeda's attempts to restore its dwindling presence in Afghanistan are also running into problems, the officials say. Al Qaeda was forced out of Afghanistan by the U.S.-led invasion that ousted the Taliban in 2001, and it reestablished itself across the border in Pakistan, where Osama bin Laden and other leaders are thought to have taken refuge.
Al Qaeda is believed to have fewer than 100 operatives still in Afghanistan. Though mounting attacks there is not the network's main focus, it remains interested in striking U.S. and other targets.
But its capabilities have been degraded in recent years, and such attacks now require assistance from the Taliban or waiting for fleeting opportunities, such as the suicide bomber attack on a base used by the CIA in Khowst province in December by a Jordanian double agent who had promised U.S. officials intelligence about Al Qaeda's No. 2, Ayman Zawahiri.
Last year, the organization began offering stipends to Afghans who would escort its operatives into the country, but there are indications that many Taliban are refusing this inducement, one U.S. official said.
"The Afghan Taliban does not want to be seen as, or heard of, having the same relationship with AQ that they had in the past," said the senior official, who is familiar with the latest intelligence and used an abbreviation for Al Qaeda. The officials and others described the assessments on condition of anonymity.
Indications of Al Qaeda-Taliban strains are at odds with recent public statements by the Obama administration, which has stressed close connections among militant groups to help build support from the Pakistani government and other allies to take them on all at once.
U.S. officials remain unsure whether the alliance between Al Qaeda and the Afghan Taliban is splintering for good, and some regard the possibility as little more than wishful thinking. A complete rupture is unlikely, some analysts say, because Al Qaeda members have married into many tribes and formed other connections in years of hiding in Pakistan's remote regions.
But the tension has led to a debate within the U.S. government about whether there are ways to exploit any fissures. One idea under consideration, an official said, is to reduce drone airstrikes against Taliban factions whose members are shunning contacts with Al Qaeda.
One of the goals of the U.S. effort in Afghanistan and Pakistan is to isolate extremists, both within Al Qaeda and the larger Taliban movement, while encouraging low- and mid-level Taliban fighters to renounce ties with Al Qaeda and reconcile with the Afghan government.
Tactics such as drone strikes and a stepped-up campaign of targeted killings by U.S. Special Operations troops and an intensified military campaign in both Pakistan and Afghanistan have raised the risks to Taliban fighters who assist Al Qaeda, the senior U.S. official said.
The arrest in recent months of several top Afghan Taliban leaders may also be leading some Taliban to reassess their ties to Al Qaeda in hopes of easing pressure from the Inter-Services Intelligence, Pakistan's spy agency, which long allowed the Afghan Taliban to operate relatively unbothered.
Officials acknowledge there is little evidence to suggest that Mullah Mohammed Omar, the top Afghan Taliban leader, favors cutting ties with Bin Laden and other top Al Qaeda leaders, relationships that go back nearly two decades.
"Al Qaeda has been a very valuable resource to the Taliban in the past," said a U.S. official, who is skeptical of the new intelligence. "And I haven't seen the evidence they really want to cut them loose."
Unease with the continuing relationship is most apparent among the Taliban's mid-level commanders and their followers, the U.S. officials said.
Though they have a common enemy in the United States and a common interest in maintaining their sanctuary, Al Qaeda and the Afghan Taliban have seen their goals diverge somewhat.
The Taliban has focused on moderating its image as part of its campaign to retake power in Afghanistan. Al Qaeda has drawn closer to other militant groups in Pakistan's tribal belt that are seeking to overthrow the Pakistani government.