South African police say a truck driver could be charged with manslaughter after his vehicle collided with a train, killing 18 people and injuring about 260 others.

Police official Motantsi Makhele said Friday that "a case of culpable homicide has been opened" following the crash Thursday in Free State province.

Authorities say the truck driver erred by allegedly trying to cross the tracks just ahead of the oncoming train.

Part of the train burst into flames after the collision, trapping some passengers in carriages. Makhele says a final death toll cannot be announced until a forensic investigation including DNA testing is complete.

Workers were checking under the carriages for any other remains.

The train with 429 passengers aboard had been traveling from Port Elizabeth to the country's commercial hub, Johannesburg.