A fire broke out at the University of South Africa's (Unisa) Muckleneuk campus in Pretoria on Tuesday night, destroying parts of the Winnie Madikizela-Mandela building.

According to City of Tshwane Emergency Services Department spokesperson Thabo Charles Mabaso, firefighters were called to the scene on Wednesday shortly before 01:00.

Mabaso said firefighters saw the dense smoke billowing from the building even before they arrived on the scene.

He said firefighters battled to gain entry to the building through the three wooden and two steel roller doors and had to be assisted by campus security officers, who made use of their access cards.

Upon arrival, "firefighters managed to locate the fire inside the building after battling to open multiple doors and going through stacks of files, books and furniture," he said. 

"Firefighters found stacks of books and files smouldering in various places on the second floor and extinguished them. Most of the second floor suffered extensive smoke and water damage, and part of the third floor also suffered some smoke damage," Mabaso added.

Mabaso said an aerial ladder apparatus was used to open windows, and mechanical ventilation was conducted to rid the building of excessive smoke. He said the flames were doused within two hours.

According to Mabaso, a source at the scene claimed that a fire had broken out at the same building two weeks ago, but that it was extinguished by staff. Emergency services were not notified.

Meanwhile, Unisa confirmed the latest incident. It said management had decided to close the Winnie Madikizela-Mandela building for health and safety reasons so that an investigation could be conducted.

"At the time of the incident, no injuries were reported. The cause of the fire and the extent of the damage will form part of the investigation," the university said in a statement.

An investigation report would be compiled and guide management with future steps, Unisa added. It said it would communicate with the affected staff.