A homicide bomber struck a restaurant in volatile northwest Pakistan on Thursday, killing at least 11 people including militants opposed to the country's top Taliban commander, intelligence officials said.

Pockets of northwest Pakistan are strongholds for Taliban, Al Qaeda and other militant groups, not all of whom get along.

Even as Pakistan has battled the extremists and the U.S. has carried out dozens of missile attacks against the militants — including a suspected American strike that killed eight Wednesday — the armed groups have also attacked one another.

The attack Thursday morning occurred just outside the South Waziristan tribal region near the town of Tank at a roadside restaurant where some two dozen militants loyal to Turkistan Bittani were eating, two intelligence officials told The Associated Press.

Several other people were wounded in the attack, said the officials, who spoke on condition of anonymity because they were not authorized to the speak publicly to the media.

Bittani was not present. South Waziristan is the stronghold of Baitullah Mehsud, a Bittani rival.

The tribal region also was the target of Wednesday's alleged U.S. missile strike, whose death toll included several foreigners, according to two other intelligence officials said. Wednesday's strike damaged two vehicles near Makeen, a town that borders Afghanistan.

The strike came as President Barack Obama's administration prepares to unveil a new strategy to quell Islamist insurgents threatening Pakistan and neighboring Afghanistan.

American officials have indicated that attacks along Pakistan's un-policed western frontier, apparently carried out by unmanned CIA aircraft and stepped up since last year, will continue despite protests from the Pakistani government.

The officials discussed the missile strike on condition of anonymity because they also were not authorized to speak to the media. Reporters cannot verify reports from the area because authorities and militants limit access.

U.S. officials say the strikes have killed a string of militant leaders and put Al Qaeda on the defensive in an area considered a possible hiding place for its fugitive leaders, Usama bin Laden and Ayman al-Zawahri.

However, the Pakistani government argues that the tactic is counterproductive because it kills civilians, stokes anti-American feeling in the Islamic world's only nuclear-armed country and undermines its own efforts to isolate extremists.