Twenty people were killed when two minibuses and a truck collided in South Africa on Tuesday, police said. The accident occurred on a highway Leeu-Gamka and Prince Albert Road in the Western Cape Province before dawn. The victims, including two children, were passengers in the taxis. The exact cause of the crash was still under investigation, police spokesman Malcolm Pojie told the South African Press Agency (SAPA). Minibus taxis are the backbone of the country's transport network.