The victims comprised of an assistant police sub-inspector and three members of the Frontier Corps, a paramilitary force which uses recruits from Pakistan's tribal areas and is overseen by Pakistani army officers.

CNN: Suicide attack kills 4 in Pakistan

Malik Naveed, the inspector-general of police of the insurgency-hit North West Frontier Province (NWFP), said this month that Taliban groups had merged with al-Qaeda and were spreading rapidly across the country.

ECONOMIST: Pakistan's extremists: The slide downhill | The