At least six people, including four policemen, were killed when a roadside bomb went off near a police van in north-western Pakistan, officials said on Sunday. The incident took place late Saturday some 50 kilometres south of Peshawar, the capital of the Khyber-Pakhtunkhwa province, according to a report of DPA. Ahmad Khan, a police official said the bomb was planted in a cart and went off when the police van drove by. Eight people, including six policemen, were injured.