Updated

South African police say they arrested nine people during overnight arson attacks and stone-throwing near the University of the Witwatersrand, where students have been protesting for free education.

The national police said Saturday that two vehicles were set on fire in the overnight rioting in Braamfontein, an urban area of Johannesburg that was the scene of similar violence during clashes between students and police earlier in the week.

The University of the Witwatersrand has imposed overnight restrictions on access and movement on campus grounds because of security concerns.

In other overnight violence, South African media say two buildings were damaged by firebombs at the Howard College campus of the University of KwaZulu-Natal.

Student protests, many of which have turned violent, have forced some South African universities to close.