South Africa unrest over ANC's Tshwane candidate
Police are battling to quell violence that has broken out in the area around South Africa's capital, Pretoria.
A government statement calling for calm said police officers "came under fire as protesters allegedly attacked their car with stones".
Trouble broke out in the Tshwane area reportedly over the mayoral candidate chosen by the governing ANC for August's elections.
The tension relates to factionalism within the party, analysts say.
Local media are showing pictures of burning barricades blocking main roads.
South Africa's government has called for dialogue to sort out the problem.
Some ANC members in the city are said to be angry that current mayor Kgosientsho Ramokgopa was pushed aside in the nomination process.
But Mr Ramokgopa has said he is happy with the selection of Thoko Didiza, reports South African news channel EWN.
"I really want to call for calm [and] call for people not to disrupt other people's lives. Let's allow this election to unfold in a free and fair manner," he is quoted as saying.
The ANC is tearing itself apart: Milton Nkosi, BBC News, South Africa
The chaotic situation playing itself out is symptomatic of a wider problem of factionalism that has plagued the ANC.
This is about an ANC that is tearing itself apart partly because of the politics of patronage and the cancer of corruption.
At the heart of these violent protests is the hypnotic inner voice repeatedly playing in the minds of those burning and pillaging: "It's our time to eat, it's our time to eat."
The idea that the selection of one mayoral candidate over another could spark so much anger is clearly not the main reason.
This is about those who hold the public purse in the name of the people and are refusing to relinquish it to their rivals.
The ANC may have been correct in parachuting Thoko Didiza, who comes with an impeccable track record, as a compromise but that clean slate does not matter in the eyes of those at the bottom of the food chain.
A local ANC leader has said there would be more protests as the "people's mayor" has been dropped, South Africa's News24 website reports.
The authorities have warned that perpetrators of violence "will face the full might of the law".
Local elections are due in South Africa in August, with the ANC under increasing pressure over its handling of the economy and accusations it has failed to tackle corruption.