Pakistani authorities searched Sunday for the possible wreckage of an American pilotless drone reported to have crashed in a northwestern militant stronghold, the military's top spokesman said.

The CIA is believed to operate the drones, which have been used in an escalated U.S. campaign of missile strikes against Al Qaeda and Taliban targets in Pakistan's remote northwest regions bordering Afghanistan. The U.S. rarely discusses the missile attacks and an American military spokesman in Afghanistan declined to comment on Saturday's reports of a downed drone.

The reports came from Angoor Ada village in South Waziristan, a tribal region where the main Pakistani Taliban leader, Baitullah Mehsud, is based. Tribesmen, soldiers, intelligence agents and informants were hunting for possible aircraft remains in the rough terrain.

"We haven't found any wreckage, but we are still searching," Pakistan army spokesman Maj. Gen. Athar Abbas said Sunday morning.

Haibib Wazir, who runs a telephone center in Angoor Ada, said he did not hear any shooting Saturday, despite speculation that militants might have fired at a drone.

He said he encountered soldiers and tribesmen who came back empty-handed after searching the thick, wooded area for the wrecked drone Saturday. They could "make money by handing that wreckage to the Taliban," Wazir said.

Militants are believed to use pockets of Pakistan's northwest as bases to plan attacks on U.S. and NATO forces in Afghanistan. The missile strikes, however, prompt routine protests from Pakistani officials who say the attacks fuel anti-American sentiment.

Pakistan's military has conducted offensives against insurgents in the northwest, especially the lawless tribal regions, where Al Qaeda leader Usama bin Laden and his deputy Ayman al-Zawahri are rumored to be hiding. Officials recently said they had defeated the militants in Bajur tribal region and were close to victory in the adjacent Mohmand tribal area.

Pakistani militants have been blamed for the November attacks in Mumbai that killed 164 people, and Pakistan has acknowledged at least part of the attack was planned on its soil.

The secretary-general of Interpol, on a visit to Islamabad on Sunday, noted that Pakistan has agreed to provide DNA evidence from its probe into the Mumbai attack to check against the international police agency's databases.

Ronald Noble said Indian cooperation was critical.

"In order for these comparisons to be complete, India will be required to send Interpol the DNA profiles that they have obtained in their investigation as well," Noble said at a news conference.

Late Saturday in Mohmand, suspected Taliban fighters attacked security forces in the Salam Koroona area, killing 13 tribal police officers, government official Rasul Khan said.

The U.S. has praised Pakistan's military offensives in the tribal areas, but it is concerned about Pakistani efforts to negotiate peace with Taliban fighters in the nearby Swat Valley.

As part of those talks, the government has agreed to enforce Islamic law in the valley, a one-time tourist haven. On Saturday, officials announced they would release 12 Taliban prisoners as part of the talks.