A suicide bomber rammed his explosive-laden car into a vehicle carrying paramilitary forces in northwestern Pakistan on Tuesday, killing at least four troops and wounding several people, including schoolchildren, police said, AP reported.

The attack happened near a checkpoint on the outskirts of Peshawar, the provincial capital of the volative North West Frontier Province, where the military last week launched an offensive against Taliban militants to halt their push toward the capital, Islamabad.

Eight officers and some schoolchildren were wounded in the attack, senior police officials Safwat Ghayur said, adding that the dead and injured had been transported to hospitals.

Ghayur declined to speculate who was behind the attack, but authorities have blamed Taliban militants for a string of such attacks since Pakistan became a key ally of Washington in the war against terror after the Sept. 11, 2001 attacks in America.

The militants also have been angered over the continuing military operations against them in the troubled northwestern districts of Buner, Dir and elsewhere where the military says it has killed scores of insurgents.

A senior police official says a suicide car bomber has killed at least four paramilitary security forces in northwestern Pakistan.

Senior police official Safwat Ghayur says the attacker rammed his explosive-laden car into a vehicle carrying troops Tuesday near a checkpoint on the outskirts of northwestern city of Peshawar.

Ghayur says eight officers also were wounded in the attack.