The MEC said the robbers, who were visibly armed with a gun and knives, demanded valuables from teachers and pupils.
The pupils stood their ground and refused to be bullied by the robbers. However, the robbers overpowered the pupils and stabbed them.
The perpetrators made off with cellphones, money and other valuable items. The injured pupils have been admitted to hospital.
One suspect was arrested by the police. The other two suspects are still at large.