Thirty-eight people - including several children - were left injured when a bus and truck collided on the R511 in Diepsloot, Johannesburg, on Monday morning.
The children were on their way to school when the bus they were travelling in crashed into a truck, ER24 said in a statement.
"ER24 paramedics, along with several other services, arrived on the scene at approximately 07:30 to find a large truck on the side of the road on its roof," ER24 spokesperson Russel Meiring said.
"A bus was found parked in the road a short distance away. Local authorities began to close off the road while paramedics set up a triage area.
"On assessment, paramedics found that that 38 people, including several children, had sustained critical to minor injuries.
"One of the critically injured, a man, lay trapped inside the cab of the truck.
"Rescue services had to use specialised rescue equipment to free the man from the vehicle. Once freed, paramedics treated the patients and provided the critically injured patients with advanced life support interventions," Meiring said.
According to a statement by Netcare 911, many of the children sustained injuries ranging from minor to serious.
"One child was found to be in a critical condition and due to the nature of the injuries, Emer-G-Med EMS activated the Netcare 911 helicopter air ambulance," it said in a statement.
Emer-G-Med chief operating officer Jurgen Kotze told TimesLive that the bus and truck collided on the R114 and R511 at 06:50.
"...patients have been treated for a number of injuries, including fractures and burns," he reportedly said.
"Circumstances leading to the collision are at this stage unknown; however, the SAPS were on scene and will be investigating," Netcare 911 said.