Police arrested 15 pupils and six other people during protests in Maokeng in Kroonstad on Wednesday, police said.
Spokesman Maselela Langa said protesters had been burning tyres and blockading roads in the Maokeng township since Tuesday.
Fifteen pupils were arrested for public violence after they raided high schools in the area forcing other pupils to join the protest, Langa said.
Classes were interrupted at the Bodibeng Secondary School after protesters pulled pupils from the school.
“Nobody was hurt in the process, but it was total chaos. We had to release the pupils before things got out of hand;” said a school teacher who did not want to be named.
Langa said protesters were angry about electricity cuts in the area.
Six other protesters were arrested for malicious damage to property.
Police were monitoring the situation. – Sapa