Up to 20 people were killed near Cape Town on Monday when a train smashed into a truck carrying farm workers in one of South Africa's deadliest rail accidents in years, police and emergency workers said.
All the victims died at the scene of the crash near Croydon, about 40 kilometres (25 miles) east of Cape Town, said Chris Botha, a spokesman for the Netcare 911 rescue service.
Botha said 20 people were killed and at least six others were either seriously or critically injured.
According to Cape Town emergency services spokesman Johan Minnie the truck was on a level crossing when it was hit by the train shortly after 7:00 am (0500 GMT).
The vehicle was sliced in half by the impact of the collision and the wreckage was widely scattered around the tracks, said an AFP photographer at the scene. The train did not derail and came to a stop about 500 metres from the point of impact.
The railway safety regulator (RSR) said an investigation had been launched to determine the cause of the crash.
"The RSR has dispatched inspectors to the scene of the accident to work alongside the operator in investigating this incident," it said in a statement.
"Preliminary investigations suggest that the immediate cause of the accident was that the driver ignored warning signals and proceeded to cross the level crossing resulting in the collision with the train."
A police spokesman said it was too early to give an exact cause for the crash.
"We don't know whether to blame it on a mechanical failure or a failure to stop," Superintendent Billy Jones told AFP.
He put the death toll at 19 -- 11 men and eight women. Twelve others were injured, Jones said.
The group had been on their way to work at a wine farm in the area.
"This is a terrible day. It is a great disaster. They were just innocently coming to work," a staff member of the farm which employed the workers on contract told the South African Press Association.
Many of the passengers on the train were high school pupils on their way to writing year-end exams, said sources at the scene.
Four of the injured, three men and a woman, were admitted to the Tygerberg Hospital in the nearby Parow Valley in a stable condition, said hospital spokeswoman Martie Carstens.
Another four were taken to the Vergelegen medi-clinic in Somerset West. One was due to undergo surgery later in the day, while the condition of the other three was not immediately known.
No train passengers were injured, but the driver was treated for shock.
The government-owned rail passenger service Metrorail said the level crossing where the collision happened "conforms to legal requirements in terms of statutory warning signage and is protected by stop boards, road warning signs and train whistle boards".
Transport Minister Jeff Radebe expressed shock at the deaths and called for a speedy, thorough investigation by the RSR and the South African Rail Commuter Corp.
"Minister Radebe is being briefed on the developments of the investigation as it unfolds and the ministry will issue a detailed statement as more information becomes available," his office said in a statement.
The crash was one of the worst in South Africa in recent years. Nine people died and 59 were injured in April last year when a bus rammed into a freight train in the northern Limpopo province.
Twenty-four people, mainly school children, were killed in a train collision near the eastern city of Durban in the province of KwaZulu-Natal in 2002.