ISLAMABAD, Pakistan -- A recent series of assassination attempts on high-level officials here is the result of a growing and deadly alliance between Pakistani extremists and second-rung al Qaeda operatives from Arab countries and Central Asia who use the border area with Afghanistan as a refuge, according to senior Pakistani intelligence sources.
The development is a disquieting one, foreign diplomats said, because it suggests that Pakistan's security services may be losing control over home-grown militants they once embraced as allies, first in the struggle against the Soviets in Afghanistan and more recently against Indian forces in Kashmir.
Police officers sealed off an area in Karachi in June after the attempted assassination of a top Pakistani commander.
An attack on Lt. Gen. Ahsan Saleem Hayat, a top military commander, on June 10 was conducted by Pakistani assailants who later confessed they had been trained in small arms, explosives and conducting ambushes at an al Qaeda camp in Pakistan's rugged tribal region of South Waziristan, near the Afghan border, according to two senior intelligence officials.
The gunmen identified their instructors as Uzbeks and Arabs.
The Pakistani extremists, disguised in military-style uniforms, attacked Hayat as they waited in a stolen van in the port city of Karachi near a bridge frequented by military officials, then opened up with machine guns on his motorcade.
Hayat survived the carefully planned ambush, but 11 others were killed, including his driver. The assailants were quickly identified and rounded up, traced through a cell phone left at the scene, authorities said.
Pakistani officials said they believed that foreign al Qaeda operatives working with Pakistani militants were also behind two attempts to kill Gen. Pervez Musharraf, Pakistan's president, in December.
The same combination, they said, may have carried out the July 30 assassination attempt against Shaukat Aziz, then the finance minister, who became prime minister on Saturday.
"For a foreigner to operate in Pakistan has become more and more difficult, so obviously their effort is to use local operatives," said one of the senior intelligence officials, who spoke on condition that neither he nor his organization be identified.
On Monday, government troops killed four foreign fighters and wounded several others in a shootout in a remote tribal section on the Afghan border, authorities said. On Aug. 21, authorities announced the arrest of up to 10 al Qaeda suspects, including Pakistanis and two Egyptians, after breaking up what they said was a plot to launch attacks against the U.S. Embassy and Musharraf's residence, among other targets.
The decision to apply stronger pressure on militants poses a delicate challenge for Musharraf, who is eager to confront the domestic terrorist threat and has recently won international praise following a series of high-profile al Qaeda arrests in Pakistan in June and July.
At the same time, Musharraf is reluctant to challenge extremist groups he still regards as potential levers in the conflict with India over control of Kashmir, even though the groups theoretically have been banned, analysts said.
In an interview with a Pakistani newspaper this month, Musharraf said the groups would not "pack up" until India and Pakistan reached a settlement on Kashmir, which Pakistan regards as the key issue in peace negotiations between the nuclear-armed neighbors.
"What he's saying is, 'If there's movement on Kashmir, it will strengthen my hand to move even more strongly against these people,' " the senior intelligence official said.