At least three policemen were reportedly killed and about five others were wounded in a suicide blast Friday evening in Pakistan\'s northern district, said police. A suicide bomber blew himself up when police stopped him at a police checking-post in Lakki Marwat district of Khyber-Pakhtunkhwa province, police sources told KUNA. According to initial reports, said sources, three policemen were killed and five others were wounded. Lakki Marwat district in known for sectarian violence and is located at border with the troubled tribal region.