Countrywide protests demanding free tertiary education in South Africa entered a third week as police fired stun grenades and arrested 31 students at Johannesburg's University of the Witwatersrand.
Demonstrations since last year over the cost of university education - prohibitive for many black students - have highlighted frustration at the inequalities that persist more than two decades after the 1994 end of white minority rule.
The current protests were triggered by a government recommendation that 2017 tuition fee increase be capped at 8 percent - above South Africa's current inflation rate of 6 percent.
Critics have said that the increase would further disadvantage black students, already under-represented.
Several students hurled rocks at the main building of the university known as "Wits" after they were prevented from entering by private security guards who retaliated by throwing rocks back at the students.
Weeks of violent demonstrations last year over university costs forced President Jacob Zuma to rule out fee raises for 2016 but university authorities have warned that another freeze for this year could damage their academic programmes.
Earlier this month, 32 students were arrested after arsonists torched a law library at South Africa's University of KwaZulu-Natal following days of protests by students over the cost of tuition