JOHANNESBURG : Gunmen stormed an informal settlement near Johannesburg and shot dead 12 people overnight, South African police said Wednesday.

It was the latest mass shooting in the crime-weary country, where more than 60 homicides are recorded on average each day.

The attack happened shortly after 11:00 pm Tuesday after more than 10 armed people were driven to the area and stormed the settlement, a police spokeswoman said.

"The suspects allegedly entered the informal settlement through both entrances and moved through the area, opening fire on residents and community members at multiple locations before fleeing the scene in the same vehicle," she said.

"Preliminary investigations reveal that 12 people died as a result of the attack," Colonel Dimakatso Nevhuhulwi said.

"Eight adult males and three adult females were declared dead at the scene," she said. One person died in hospital.

The attack was in an area called Cleveland about six kilometres (less than four miles) east of the Johannesburg city centre.

Nevhuhulwi said the motive for the attack was not yet known and no arrests had yet been made.

South Africa is awash with legal and illegal firearms, and shootings are common, often fuelled by gang rivalry and competition between informal businesses.