Peshawar: Three soldiers and a passer-by were killed by a suicide bomber who rammed a car into a military convoy in a northwestern Pakistan on Wednesday, police and residents said.

The bomber rammed his car into a convoy for the paramilitary Frontier Corps convoy, 32 kilometres northwest of the city of Peshawar city, near the Mohmand region.

"After the attack, the vehicle caught fire and we have reports of three security people and a civilian killed," said a police official who declined to be identified.

Shopkeeper Abdul Qadeer said troops had opened fire after the blast but caused no casualties.

Meanwhile, earlier on Wednesday, the military used artillery and jet fighters to attack militant hideouts in Mohmand but there was no immediate word on casualties, security officials said.