Several people were also injured, local authorities said.
The incident unfolded shortly after midnight, when a group of men armed with rifles and 9-millimeter pistols entered the bar in the Nomzamo informal settlement near Johannesburg and started shooting “randomly” at the patrons, Gauteng Police said in a statement.
Police said 23 people were shot in the establishment — 12 died at the scene and 11 were rushed to a nearby hospital with injuries. At least two more people were declared dead at the hospital.
The suspects are still on the run, according to police, who have called on witnesses to come forward.
“It’s a bad scene. When you see the bodies [that] are piled up, you can see that every one of those people [was] struggling to get out of the tavern,” Gauteng Police Commissioner Elias Mawela told South African news channel ENCA.
Mawela said the police are yet to determine details on the motive or why the people at the tavern were targeted.
“I have no doubt that with the cooperation of the community here, we will be able to crack this case,” he added.
‘Every single violent death is unacceptable’
In a separate shooting incident in a bar in Sweetwaters in Pietermaritzburg on Saturday evening, four other people were also killed, police said Sunday.
The Provincial Commissioner of KwaZulu-Natal, Lieutenant General Nhlanhla Mkhwanazi, said in a statement that at least 12 people were shot after two men entered the tavern and “randomly opened fire.”
As in the Soweto shooting, police said the suspects were still at large and a manhunt was under way.
In the wake of the violence, South African National Civic Organisation in Gauteng called on the government to reinforce gun regulations in the country, according to SABC.
South African President Cyril Ramaphosa meanwhile expressed his condolences to the families of those who were killed in both attacks according to a statement from his office on Sunday.
“As a nation, we cannot allow violent criminals to terrorise us in this way, regardless of where such incidents may occur, Ramaphosa said, “As government, citizens and structures of civil society we must all work together even more closely to improve social and economic conditions in communities, reduce violent crime and stamp out the illicit circulation of firearms.”
“Every single violent death is unacceptable and worrying, and killings on the scale we have seen in Soweto, Pietermaritzburg and previously Khayelitsha must spur us into a collective effort to build communities and make South Africa an unsafe place for criminals,” he said.
Reporting contributed by CNN’s Hira Humayan.