US drone strikes left 11 militants dead near Pakistan's Afghan border yesterday, while a suicide bomber killed four soldiers in Pakistani-controlled Kashmir.

Attacks by unmanned US spy planes and suicide bombings blamed on the Taliban have soared in the past year, with Washington determined to wipe out militant sanctuaries and the extremists vowing fierce retaliation.

A drone fired two missiles into a mud-brick fort in Sanzali village, about 30 kilometres west of Miranshah, the main town in North Waziristan, in the fourth suspected US missile attack in the tribal district in a week.

Just over an hour later, a drone slammed another missile into a group of militants sifting through the wreckage, searching for survivors and picking out the dead bodies, Pakistani security officials said.

"Five militants were killed in the previous attack and six in this attack," a senior security official in the northwestern city of Peshawar said.

The area is a stronghold of Hafiz Gul Bahadur, who fought with the Taliban when US-led troops invaded Afghanistan and is reputed to control up to 2,000 fighters whom he sends across the border but who do not attack in Pakistan.