WASHINGTON — An intense, six-month campaign of Predator strikes in Pakistan has taken such a toll on Al Qaeda that militants have begun turning violently on one another out of confusion and distrust, U.S. intelligence and counter-terrorism officials say.
The pace of the Predator attacks has accelerated dramatically since August, when the Bush administration made a previously undisclosed decision to abandon the practice of obtaining permission from the Pakistani government before launching missiles from the unmanned aircraft.
Since Aug. 31, the CIA has carried out at least 38 Predator strikes in northwest Pakistan, compared with 10 reported attacks in 2006 and 2007 combined, in what has become the CIA's most expansive targeted killing program since the Vietnam War.
Because of its success, the Obama administration is set to continue the accelerated campaign despite civilian casualties that have fueled anti-U.S. sentiment and prompted protests from the Pakistani government.
"This last year has been a very hard year for them," a senior U.S. counter-terrorism official said of Al Qaeda militants, whose operations he tracks in northwest Pakistan. "They're losing a bunch of their better leaders. But more importantly, at this point they're wondering who's next."
U.S. intelligence officials said they see clear signs that the Predator strikes are sowing distrust within Al Qaeda. "They have started hunting down people who they think are responsible" for security breaches, the senior U.S. counter-terrorism official said, discussing intelligence assessments on condition of anonymity. "People are showing up dead or disappearing."
The counter-terrorism official and others, who also spoke anonymously, said the U.S. assessments were based in part on reports from the region provided by the Pakistani intelligence service.
The stepped-up Predator campaign has killed at least nine senior Al Qaeda leaders and dozens of lower-ranking operatives, in what U.S. officials described as the most serious disruption of the terrorist network since 2001.
Among those killed since August are Rashid Rauf, the suspected mastermind of an alleged 2006 transatlantic airliner plot; Abu Khabab Masri, who was described as the leader of Al Qaeda's chemical and biological weapons efforts; Khalid Habib, an operations chief allegedly involved in plots against the West; and Usama al-Kini, who allegedly helped orchestrate the September bombing of the Marriott Hotel in the capital, Islamabad.
Al Qaeda's founders remain elusive. U.S. spy agencies have not had reliable intelligence on the location of Osama bin Laden since he slipped across the Pakistan border seven years ago, officials said. His deputy, Ayman Zawahiri, remains at large after escaping a missile strike in 2006.
But the Predator campaign has depleted the organization's operational tier. Many of the dead are longtime loyalists who had worked alongside Bin Laden and were part of the network's hasty migration into Pakistan in 2001 after U.S.-led forces invaded neighboring Afghanistan. They are being replaced by less experienced recruits who have had little, if any, history with Bin Laden and Zawahiri.
The offensive has been aided by technological advances and an expansion of the CIA's Predator fleet. The drones take off and land at military airstrips in Pakistan, but are operated by CIA pilots in the United States. Some of the pilots -- who also pull the triggers on missiles -- are contractors hired by the agency, former officials said.
Predators were originally designed as video surveillance aircraft that could hover over a target from high altitudes. But new models are outfitted with additional intelligence gear that has enabled the CIA to confirm the identities of targets even when they are inside buildings and can't be seen through the Predator's lens.
The agency is also working more closely with U.S. special operations teams and military intelligence aircraft that hug the Pakistan border, collecting pictures and intercepting radio or cellphone signals.
Even so, officials said that the surge in strikes has less to do with expanded capabilities than with the decision to skip Pakistani approval. "We had the data all along," said a former CIA official who oversaw Predator operations in Pakistan. "Finally we took off the gloves."
The Bush administration's decision to expand the Predator program was driven by growing alarm over Al Qaeda's resurgence in Pakistan's tribal belt.
A 2006 peace agreement between Islamabad and border tribes had allowed the network to shore up its finances, resume training operatives and reestablish connections with satellite groups.
The Bush administration had been constrained by its close ties with Pakistani President Pervez Musharraf, who argued against aggressive U.S. action. But by last summer, after a series of disrupted terrorist plots in Europe had been traced to Pakistan, there were calls for a new approach.