At least four people were killed and eight others injured when two cars exploded in Nigeria's northeastern state of Borno, according to the Nigeria delegation of the International Committee of the Red Cross.The incident occurred in Dikwa, a town located 90 km east of Maiduguri, the state capital, said Aliyu Dawobe, a spokesman for the Red Cross.Two vehicles blew up on suspected improvised explosive devices, Xinhua reported."Five of the most seriously injured victims are now being treated by the ICRC surgical team at the State Specialist Hospital, Maiduguri, while another was referred to the University of Maiduguri Teaching Hospital," the Red Cross spokesman added.No group has claimed responsibility for the explosions.