Six people were injured and 30 were arrested during a protest over housing delivery in Sebokeng on Tuesday morning, Vaal Rand police said.
Captain William Mcera said about 800 protesters burned tyres and stoned vehicles from about 4am, opposite the Sebokeng Hospital in Zone 14.
They said they were unhappy that housing delivery had taken place in the area.
A number of the 50 policemen on the scene were injured in the protest and police vehicles and windscreens were damaged.
Mcera said it was not yet clear how many the protesters had been injured.
A group called the Cape Anti-War Coalition said it had been told that police had shot at the protesters. Mcera said an investigation would be conducted to establish how the injuries were incurred.
Protesters also blocked Moshoeshoe street and the railway line between Residensia and Sebokeng, forcing Metrorail to suspend services between Johannesburg and Vereeniging.
Preliminary reports indicated that protesters had damaged signalling infrastructure and trains had been stoned and drivers intimidated.
The service would only run from Johannesburg to Residensia, said Metrorail spokesperson Brenda Motau.
Those arrested would be charged with public violence. – Sapa