Twenty-eight people have been arrested at a university in South Africa while protesting against a racially offensive video which emerged last week.
The video shows white students at the University of Free State allegedly forcing black employees to eat food that had been urinated on.
The university authorities said the arrests had been made for intimidating lecturers and other students.
More security guards are being posted across the campus, said the university.
"Students who are aggrieved by the video are suspected to be carrying out the intimidation," said university spokesman Mangaliso Radebe. "Tension is still high on the campus following the release of the video."
The incidents included the heckling and manhandling of a white lecturer, according to the university.
Those arrested are due to appear in court on Wednesday.
The video, thought to have been recorded in September, was made by students angered by a new integration policy at the campus in Bloemfontein.
The policy would make black and white students share university accommodation.
Two students were suspended from campus over the incident, though their lawyers deny they committed a criminal act and are quoted as saying the video was "no more than play-acting".
The South African Human Rights Commission is investigating the incident and other episodes of alleged racism at the university.
The university is known for having predominantly white students since the days of apartheid and in recent years it has encountered difficulties trying to integrate people from other racial groups.