This follows persistent US accusations that Pakistan is not doing enough to eliminate Taleban and al-Qaeda sanctuaries in the border region.

The upsurge in strikes has alarmed Pakistani military and government officials, who say it seriously undermines their counter-insurgency operations

Bodies

Villagers say unmanned US aircraft fired several missiles at a house and an Islamic seminary in the tribal area of North Waziristan.

Officials and witnesses say the complex was hit a number of times.

"There were two drones and they fired three missiles," an unnamed resident of Dandi Darpakheil, a village near Miranshah, the main town of North Waziristan, told Reuters news agency.

Other reports speak of three drones.

Some reports say the death toll could be as high as 20. Casualties include militants, as well as a number of civilians.

Security officials say that the house belonged to Jalaludin Haqqani, a veteran Afghan Taleban commander said to have close links to Osama Bin Laden.

Mr Haqqani and his son, Sirajuddin, who is also a Taleban commander, were not at home, another son, Badruddin, told Reuters by telephone.

Badruddin Haqqani said one of his aunts had been killed in the raid, and that women and children were among those who had been hurt.

The BBC's M Ilyas Khan says the residential-cum-seminary complex has been raided a number of times by the Pakistani army, and hit by aerial attacks from across the border with Afghanistan.

Mr Haqqani has maintained the complex since 1980 and family, clansmen and militants still use the premises, our correspondent says.

Our correspondent says militants immediately cordoned off the entire area and shifted bodies dug up from the debris elsewhere.

Officials in Miranshah say they still do not have evidence that any high-value target may have been hit.

Rising tensions

In recent months, US forces based in Afghanistan have been accused of stepping up attacks against suspected Taleban targets over the border in Pakistan's tribal region.

Last week Pakistan condemned an alleged raid by foreign troops based in Afghanistan, which officials say killed at least 15 villagers in South Waziristan.

In the same week, at least 10 people were killed in two suspected US missile strikes on alleged militant targets in North Waziristan.

Pakistan's army has warned that such direct US action could rally more tribesmen behind the Taleban and incite a wider uprising, our correspondent says.