Protesters in Intabazwe township near Harrismith have damaged a municipal building, Free State police said on Friday.

The protests began on Thursday night after 7.00pm when residents gathered, said Sergeant Mmako Mophiring.

"They barricaded the roads, then they attacked a building where they believe councillors come and have meetings," he said.

The protesters started a tyre fire in the building but it was put out by police before major damage could be done. The windows of the building were destroyed by thrown rocks.

Mophiring said police arrested 13 men and one woman for public violence and malicious damage to property.

Police were in Intabazwe on Friday and were monitoring the nearby N3 and N5 in case those roads were blockaded by protesters.

"The situation is a little tense but still we are here," said Mophiring.