IMPHAL, March 29: Three persons, including two jawans, were killed and two others injured in a bomb explosion by militants in Manipur today although the state government extended the existing unilateral ceasefire to insurgent outfits for one more month from April 1, reports PTI. Official sources said two jawans of the 15th Jat regiment were killed on the spot and two others seriously injured when a powerful bomb, planted by militants, went off at Ichum Lairembi area, about 23 km north of here this morning. A few minutes after the explosion, armed militants opened fire from nearby Pheidinga hills forcing the securitymen to retaliate. In the ensuing encounter, one militant was killed. The injured jawans were taken to a nearby Army hospital at Leimakhong. Sources said the security forces reinforced from nearby Army headquarters launched a massive combing operation. Official sources said the bomb exploded when the Army personnel were foot patrolling from Pheidinga to Army headquarters at Leimakhong, about 25 km north of here. As the Army personnel heard Ichum Lairembi area, about two km from Pheidinga towards Army headquarters, the bomb planted by the militants exploded killing two Army personnel on the spot, source said. Two other personnel and a civilian also sustained serious injuries, sources said, adding that the Army men were moved to Army hospital while the civilian was taken to the regional Institute of Medcial Science Hospital. The explosion occurred nearly 13 hours after Manipur cabinet had decided last evening to extend the unilateral ceasefire. Sources said the Army personnel, belonging to 15th Jat Regiment, combed the area soon after the explosion but no arrest was made so far. Meanwhile, underground Kang-lei Yawol Kann Lup (Toijamba faction), in a statement last Tuesday, had rejected the unilateral ceasefire to all insurgent outfits in Manipur. Earlier, the banned Revolutionary People's Front, political wing of People's Liberation Army (PLA) and People's Revolutionary Party of Kangleipak (PREPAK) had, in separate statements, also rejected the unilateral ceasefire declared by the Government. Meanwhile, the State Cabinet has decided to extend the unilateral ceasefire to insurgent outfits for one more month from April 1. Stating that the decision was taken last night, the sources said, the current ceasefire would expire on March 31. The ceasefire was made effective from March 1.