According to senior administration officials, two high-level reports on Pakistan and Afghanistan have called for broadening the target to a major sanctuary in and around Quetta. Mullah Muhammad Omar, who led the Taliban government that was ousted in the 2001 US-led invasion, has operated out of the region for years.

The missile strikes being carried out by Central Intelligence Agency-operated drones have never been extend­ed into Baluchistan, a sprawling province under the author of the central government, which abuts the parts of southern Afghanistan where recent fighting has been the fiercest.

There remains fear within the U.S. government that extending the raids would worsen tensions. Pakistan complains that the strikes violate its sovereignty.

But some US officials say the missile strikes in the tribal areas have forced some leaders of the Taliban and al-Qaeda to flee south towards Quetta, making them more vulnerable. In separate reports, groups led by both Gen. David H. Petraeus, commander of US forces in the region, and Lt. Gen. Douglas E. Lute, a top White House official on Afghanistan, have recommended expanding US operations outside the tribal areas if Pakistan cannot root out the strengthening insurgency:

Many of Obama’s advisers are also urging him to sustain orders issued last summer by President George W. Bush to continue Predator drone attacks against a wider range of targets in the tribal areas, and to conduct cross-border ground actions, using CIA and special operations commandos.

A spokesman for the National Security Council, Mike Hammer, declined to pro­ vide details, saying, “We’re still working hard to finalize the review on Afghanistan and Pakistan that the president requested.”

Obama’s top national security advisers, known as the Principals Committee, met Tuesday to begin debating all aspects of Afghanistan-Pakistan strategy: Senior administration officials say Obama has made no decisions, but is expected to do so in coming days after hearing the advice of that group.