Four South African police officers and a driver were killed when a truck carrying blasting cartridges exploded after a crash with another lorry.
The explosives truck was rear-ended by another heavy vehicle on a road near the northern town of Polokwane in the early hours of Thursday morning.
"When the police arrived at the scene, the explosives truck caught fire and exploded," police spokeswoman Ronel Otto said.
"Four of our colleagues died at the scene, and three others were injured and taken to hospital."
She said the driver of the other truck also died, but the explosives truck driver survived.
"At this stage, we don't know the owners of the explosives truck or where it was headed," said Otto, adding that blasting cartridges were usually used in the mining industry.
Three other cars were damaged in the explosion.
Police are probing the cause and circumstances of the accident.
Hazardous goods are often transported by road in South Africa due to freight rail bottlenecks.
