A top police commander and a civilian were killed while five other cops were injured after militants attacked a police patrol party in north eastern Indian state of Assam, police said Tuesday.Police said the incident happened in Dhekiajuli area of Sonitpur district this morning when militants ambushed a police patrol team led by Additional Superintendent of Police (ASP)."The top cop ASP died on the spot while five other police constables were injured," police said. "The attack resulted in gunfight during which both sides exchanged gunfire".The police said the militants fled from the spot, but later one more body of a civilian was recovered from the spot, adding, all the injured were hospitalized out of whom three were reported to be in critical condition.The police said the militants belonged to the National Democratic Front of Bodoland (NDFB).Several insurgent groups are active in Assam. Some of them call for regional autonomy while others demand complete independence from Indian rule.