MIRAMSHAH: Suspected US spy drones fired missiles early Thursday into Pakistan's North Waziristan tribal area seen as a safe haven for al-Qaeda and Taliban militants, killing 11 people, security officials said.

The missiles hit a seminary in a village just outside Miramshah, the main town in the tribal area, residents and officials said.

'At 2:25 am, two spy drones fired three missiles at the madrassa of Mullah Mansoor. Eleven people have been killed in the missile strike,' a security official told AFP.

'Locals are still looking for more people in the rubble,' he said.

The Pakistani military said that it was gathering details about an 'incident' in North Waziristan.

'An incident has been reported from there. Details are being gathered about the exact number of casualties,' chief military spokesman Major General Athar Abbas told AFP.

Residents said that all of the victims were local tribesmen, adding that locals had fired at two suspected US drones hovering above.

There was no immediate confirmation of the strike from either the US-led coalition in Afghanistan or the Central Intelligence Agency, both of which are known to operate missile-equipped drones.

Missile strikes targeting militants in Pakistan in recent weeks have been blamed on US-led coalition forces or CIA drones based in Afghanistan.

The United States has stepped up attacks on militants in Pakistani territory since a new civilian government came to power in Islamabad in March.

Five people were killed in a similar strike last week in South Waziristan, which is a stronghold of Pakistani Taliban chief Baitullah Mehsud.

Mehsud, the head of the umbrella Taliban organisation Tehreek-i-Taliban Pakistan (TTP), was accused by Islamabad and the United States of masterminding the killing of former premier Benazir Bhutto in December 2007.

Relations have also been strained by a raid by US special operations forces into Pakistan on September 3 which killed several Pakistanis.

President Asif Ali Zardari has vowed zero tolerance against violations of his country's sovereignty amid the strikes, which have stoked anti-US sentiment in Pakistan.

US and Afghan officials say northwest Pakistan is a safe haven for Al-Qaeda and Taliban militants who sneaked in from Afghanistan after the fall of the Taliban regime in late 2001.

Al-Qaeda chief Osama bin Laden and his deputy, Ayman al-Zawahiri, are widely believed to be hiding in the area.