At least two policemen were killed and three others were injured in a bomb attack at police van here in the wee hours of Thursday morning. The attackers hurled grenades at a police patrolling van at Inqilab Road in Peshawar, killing two persons on the spot, while three others were injured in the attack. The injured were shifted to hospital, where they said to be in stable condition. Police have registered case against the unknown assailants.