When ER24 paramedics arrived on the scene they found ten vehicles and three trucks were completely blocking the entire side of the road.
Three people were injured on Monday morning after thirteen vehicles crashed on the N4 outside Middleburg in Mpumalanga.
Several vehicles were found overturned.
It is understood that a driver of a truck allegedly lost control, causing the truck to crash into several cars during a protest action.
The highway was closed-off and traffic was diverted as passengers were attended to by paramedics.
Two people were found to have sustained serious injuries while, one other had only moderate injuries
Paramedics treated the occupants and once treated, they were transported to a nearby hospital in Middelburg for further treatment.