An explosion at the main gate of Nasta Police Station in Charsada left one policeman martyred Friday afternoon. After the explosion, a heavy contingent of police from other police station rushed to the Nasta police station. Police officials said that the nature of the blast is yet to be determined. Images taken after the blast showed a damaged gate of the police station and what looked like a collapsed sewerage drain. The martyred soldier was a resident of Charsadda’s Bahlola area, the officials said. Meanwhile, four people were wounded in a blast in Bajaur’s Mamund tehsil.