At least four people were killed and several others injured in a remote-control explosion in Bajaur Agency area of Chamarkand, officials said on Thursday.According to security sources, the blast was of remote-controlled device, planted at roadside to target security force’s personnel who were passing through the area. The deceased include two security personnel, they added. The injured and bodies have been shifted to nearby headquarter hospital. Two of the injured are in critical condition. Security forces cordon off whole area after the blast and started search operation.