One person was killed and two others sustained injuries in a hand grenade attack in a house near Manghopir police station on Thursday. According to police sources, some unidentified armed men ridding on motorcycles started indiscriminate fire in Mashki Para near Manghopir police station and later hurled hand grenade at a house, killing one person and injuring two others.The assailant managed to flee from the scene after the incident. Police and Rangers reached the spot and started investigation. Meanwhile, the city police has began to impound public buses and coaches in the name of security due to which commuters in Karachi are facing great difficulties. As a part of security plan for the Milad-un-Nabi (SAW) being celebrated today (Friday), the police stopped transport buses and coaches and ordered passengers to get off before impounding these vehicles.