At least 30 people were killed on Monday when a bus collided head-on with a truck on a highway in Nigeria's Kogi state, witnesses and rescuers said.Scores of others were injured in the accident on the Lokoja-Abuja highway, Xinhua quoted rescue volunteer Michael Akintunde as saying.Some of the victims sustained severe injures, another rescue operator Chiamaka Okafor added.The Federal Road Safety Commission confirmed the collision but declined to give official casualty figures.An official of the commission said efforts were being made to contact families of the victims.The bus was travelling from Lagos city to the capital Abuja.The accident caused traffic chaos in the area as road safety officials and police had a hectic day restoring the traffic.