“Five policemen and two paramilitary soldiers were killed in the bomb blast,” Gran Ullah, the local police station chief, said.
“A pedestrian also died in the blast,” he added.
|Timeline: Pakistan attacks|
Al Jazeera’s Kamal Hyder, reporting from Islamabad, said: “This is a very unusual and deadly attack. A car was discovered on the side of a road with a dead body of a man inside, the police then rushed to investigate.
“We are told that as they were closing in on the vehicle, it was detonated by what appears to be remote-controlled device. Police are still investigating the incident,” he said.
Violence in Pakistan has surged in recent months amid a wave of attacks blamed on Taliban fighters.
There have been regular battles with armed fighters in the north-west, particularly in the Swat valley and in the tribal region of Bajaur.