At least six police were killed in two separate attacks by Maoist militants in India's central state of Chhattisgarh, police said Monday. Four policemen were killed on Sunday night when a vehicle carrying them ran over a rebel landmine in the southern Dantewada district, according to a report of the German Press Agency "DPA". Earlier in the day, two troopers from the Border Security Force were killed in combat with rebels in the Kanker district.