At least one person was killed and six others injured during a twin bomb explosion in Indias northeastern state of Manipur, police sources said Thursday. Sources said the incident occurred in Thoubal district of Manipur on Wednesday night, adding that the bomb targeted the shacks of workers who were employed in the construction of a power house in the area. The bomb left one person dead on the spot while six others who had sustained injuries were rushed to hospital. "Few among the injured are critically injured. The death toll might increase," sources added. Earlier on August 15, a forceful explosion occurred just minutes before the celebrations of India Independence Day in the state but no casualty were reported. Later on August 18 a powerful bomb blast left three injured. Several insurgent groups are active in Manipur. Some of them call for a separate state, others for regional autonomy, while others demand complete independence from Indian rule.