Wazirdand is a small town on the edge of the tribal belt which lies outside direct government control and has been branded by US officials as the headquarters of al-Qaeda.

There has been no claim of responsibility for the attack.

On Friday, at least 33 people were killed in bomb attacks targeting a bus of Shia Muslim mourners as well as the hospital where the victims were rushed for treatment in Karachi, Pakistan's biggest city.

The Pakistani Taliban and al-Qaeda-linked fighters have been blamed by officials for the deaths of up to 3,000 people in bomb attacks across the country since July 2007.