Unknown militants blew up a girls school with explosives here in Mardan on Tuesday night. According to police militants had planted explosives device in government run girls primary school located in Sawal Dher, suburban area of Mardan, which went off with a big bang late Tuesday night. The blast completely destroyed some portions of the schools building while others were also damaged. However, no casualty or injury was reported in the explosion as school building was empty at the time of blast. It may be recalled that incidents of terrorism are on the increase in Mardan which indicate that the terrorists have set up their safe havens in and around the city.