At least 12 people were killed and nine injured on Tuesday evening when gunmen opened fire at an informal settlement in Cleveland, east of Johannesburg, police said on Wednesday.
Police said in a statement that they had launched a manhunt for more than 10 suspects following the attack at the Jumpers informal settlement.
The motive for the attack is not known.
Police said the suspects arrived in a white Toyota Quantum, entered the settlement from two access points and opened fire at multiple locations before fleeing in the same vehicle.
South Africa has one of the world's highest murder rates, averaging about 60 a day.

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