In an encounter with Maoists, four Border Security Force (BSF) jawans were killed and two others injured at Kanker in Chhattisgarh on Thursday. Earlier, it was reported that one jawan was killed and three were injured. Later on, the three injured jawans also succumbed to their injuries. Two other personnel were injured in the encounter were taken to the Pakhanjore hospital, which took place in Kanker district, the police said.