The African National Congress (ANC) in Gauteng on Wednesday urged protesting Diepsloot residents to exercise patience and tolerance as government was trying to find appropriate solutions to their problems.

At least 20 people, including a policeman, were injured on Thursday when a protest by Diepsloot residents turned violent. Protesters were demanding the removal of ward councillors and the allocation of houses.

An illegal march was organised by the party's alliance structures, the South African Communist Party, Young Communist League and the South African National Civic Organisation, said ANC Gauteng spokesman Dumisa Ntuli.

"It is a sad day for alliance structures to organise a march [for] the removal of ward councillors and the executive mayor [Amos Masondo]," said Ntuli.

He said recalling councillors was "risky in this highly contaminated political climate".

"The movement is tolerant to the growing demands on the allocation of houses. However, we need to be convinced to the rationality of the demand to remove councillors," he said.

"There is a lot of development taking place in the area hence we call for people to exercise patience, tolerance and optimism.

"Many meetings have been called and people have been informed of the integrated phase for the formalisation of the informal settlement."

Earlier, a crowd of about 100 threw stones, blocked off streets and became violent, said Pretoria police spokesperson Inspector Wanda Olivier.

Residents gathered outside a municipal office in Diepsloot Extension One at around 8am, and sang, danced and toyi-toyied.

About an hour later, police said it became violent.

"Police opened fire at the crowd with rubber bullets to control them," said Olivier.

At least 19 people and one policeman were injured. They were treated on the scene by emergency personnel.

Thirteen people were arrested for public violence and were expected to appear in the Pretoria Central Magistrate's Court on Friday.

The crowd had since been dispersed but police were monitoring the area.

Ntuli said they had had several meetings with the alliance structures to discuss the reason for the demands.

He added the alliance needed to comprehend the "good work" done by ANC councillors and Masondo.