Johannesburg – The University of Pretoria's Hatfield and Groenkloof campuses will remain closed until the institution can ensure the safety of its students and staff, it said on Friday.Vice Chancellor Cheryl de la Rey said she had decided to shut down activities at both campuses following protests on Thursday over the university's language policy."The decision to close the campuses was taken because of threats of disruption of lectures and threats of violent action in the course of yesterday [Thursday] evening."While we understand your concern over the closure, the safety of our students and staff remains paramount."She said there had been incidents of violence at universities across the country and wanted to avoid exposing students to "such high levels of risk".Media reports said 14 students were arrested and held at the Brooklyn police station following a continuation of protests against the university's language policy.However, university spokesperson Anna-Retha Bouwer said she could not confirm or deny the reports as they had not taken place on the university's premises."We are aware of the arrests that were made, but I cannot confirm that they were our students. They happened off campus," she said.Scuffles broke out between students on Thursday during a meeting attended by the AfriForum Youth, the Progressive Youth Alliance and the EFF Student Command on the language policy.Security guards and police tried to separate the groups.Bouwer at the time confirmed there had been a stand-off between members of the AfriForum Youth and the EFF Student Command. No damage to property was reported.