The South African Department of Transport has launched investigation on Thursday's train crash which left at least 18 people dead and hundreds injured.
South African Transport Minister Joe Maswanganyi said in a statement, "preliminary investigations indicate that the derailment was caused by the truck which untimely crossed the level crossing at around 09h00 this morning."
"Investigations indicate that the power car caught fire which crossed over to the next coach," said the minister.
"The derailment left 239 injured. Eighteen people have been confirmed as having burned to death in a collision involving a train and a truck in Kroonstad in the Free State," he said.
Maswanganyi visited the accident scene with other government officials. He also sent condolence messages to the families of the victims.
The Emergency Services confirmed that the Shosholoza Meyl Train 37012 was traveling from Port Elizabeth to Johannesburg when it hit a truck at Jeneva level crossing between Henneman and Kroonstad in Free State province.
Firefighters and medical personnel have rushed to the scene to help the victims.
Footages sent by passengers from the scene shows a number of carriages laid on the ground and engulfed in flames.
According to latest report from local media which cited Free State health department officials, the death toll from Thursday's train derailment in South Africa rose to 20 and the number of the injured climbed to about 260.