JOHANNESBURG (AP) — The student council at a leading South African university says a student leader was hit multiple times in the back by police rubber bullets during a protest for free education.

The council at the University of the Witwatersrand in Johannesburg said on Twitter that Shaeera Kalla, a former council head, was being treated for 13 rubber bullet wounds at a hospital Thursday.

The university says four students were injured by rubber bullets and two were hospitalized. It says police dispersed a group of protesters who had disrupted lectures and tore up test papers toward the end of a chemical engineering exam.

Sometimes violent protests for free education have hit many campuses in South Africa since last month. Some universities are struggling to finish the academic year because of the unrest.