South African students and campus security guards clashed in Johannesburg on Tuesday, hurling rocks at each other as demonstrations over higher fees turned violent.
Unrest has hit many South African universities over the past year, as students protest fee increases that they say force poorer, often black, pupils out of education.
Students and guards battled outside the Great Hall auditorium at Wits University in Johannesburg, leaving many of the building's windows broken and the ground littered with rocks before police moved in to break up the fighting.
"The students wanted to gather, and we were denied entry (to the Great Hall), that is when things turned violent," student Sizwe Mangena, 20, told AFP.
"Things started to fly, everyone running for cover. It was like a scene from the townships during apartheid.
"Our demand is simply that we want free education. Our parents can't afford to pay."
Earlier police fired stun grenades to clear a main road in Johannesburg, and students blockaded campus entrances and disrupted classes.
Tuesday's protests came a day after the government said that next year's fee hikes would be capped at eight percent.
Protests were also held at campuses in Cape Town, Pretoria and Bloemfontein.
The government said it would cover the increase for students from families earning less than 600,000 rand ($43,000, 39,000 euros) a year, but student activists have demanded free education for all.
"About 200 students in roving groups are moving from campus-to-campus disrupting classes... and intimidating students," Wits, one of the country's most prestigious universities, said in a statement on Tuesday morning.
"We are deploying security and the police. Students will be arrested if they do not comply with police orders."
TV footage showed stun grenades being fired to clear a major road in Johannesburg, while local media said that 31 people who had been arrested for blocking a campus entrance, were released with a warning.
Student medics at Wits told AFP that they had treated at least 20 injured people.
"I'm very disturbed about this because... as much as students have the right to protest, there is no basis for this protest here," Higher Education Minister Blade Nzimande told 702 radio.
"I don't like to see the sight of police in our universities. It's not good."
Last year, students -- many of them so-called "born frees" who grew up after apartheid -- staged a series of major protests which forced the government to abandon planned fee hikes for 2016.
Throughout this year, there has been sporadic unrest which has seen accommodation buildings and libraries set alight, and in May, an auditorium at Johannesburg University was firebombed.
The issue of education fees has ignited widespread frustration over a lack of opportunities for young people, worsened by a weakening economy and high unemployment.
The University of Free State closed its Bloemfontein campus Tuesday, while classes and lectures were also abandoned at the University of Cape Town.
"Burning schools, libraries and university buildings means burning the future," President Jacob Zuma said after campus riots earlier this year.