U.S. Warns Musharraf Not to Use Martial Law

Mohammad Shah, a resident, said he heard a massive explosion and went to investigate. But by the time he arrived, he said, the Taliban had cordoned off the site. "Nobody was allowed to see what happened," he said.

A local official in North Waziristan said the site that was hit had been a militant hideout.

The explosion occurred near a house formerly owned by Jalaluddin Haqqani, a veteran Taliban commander, the official said. Haqqani's son, Siraj Uddin Haqqani, has been taking on an increasingly important role in Taliban operations in recent years and is considered a vital link between the Afghan and Pakistani branches of the radical Islamic movement.

The United States is technically supposed to restrict its military activity to the Afghan side of the border, where it has tens of thousands of troops. But there have been previous episodes in which the CIA is believed to have employed Predator drones mounted with Hellfire missiles to go after targets within Pakistan. The most recent such incident occurred in June. In January 2006, the CIA tried and failed to hit al-Qaeda deputy leader Ayman al-Zawahiri in the tribal area of Bajaur.

Pakistan has been grappling with Islamic extremists on multiple fronts. On Friday, insurgents released 50 troops who they said had surrendered a day earlier during fighting in the scenic Swat Valley. There have been intense clashes in Swat over the past week, fighting that marks an expansion of the war from the tribal areas that hug the Afghan border to the so-called settled areas farther east.

Ali reported from Peshawar, Pakistan. Staff writer Walter Pincus and staff researcher Robert E. Thomason in Washington contributed to this report.