Police said it is too early to say if assaults in Soweto and Pietermaritzburg were connected.
Two bar shootings, one in a township close to Johannesburg and another in eastern South Africa, has left 19 people dead, police said.
In Soweto, 15 people were killed after as they enjoyed a night out, police said on Sunday, when assailants drew up in a minibus taxi and began randomly firing at bar patrons.
In the eastern city of Pietermaritzburg, police reported four people were killed and eight wounded during a shootout in a bar after two men fired discriminately at customers.
Police sources said it was too early to say if the assaults were in some way connected but observed their similarity.
“It saddens us that anyone now who posseses a gun wants to try their gun on our communities,” Faith Mazibuko, a member of the Executive Council (MEC) for Community Safety, told Al Jazeera.
“We wish to call upon communities to actually well indeed assist the police in bringing to book those perpetrators.”
In Soweto, Johannesburg’s largest township to the southwest of South Africa’s economic capital, police were called to the scene shortly after midnight.
“We were called in the early hours of the morning, around 12:30 am [22:30 GMT],” said police lieutenant Elias Mawela.
According to local police officer Nonhlanhla Kubheka, 12 people were already dead from gunshot wounds when police arrived at the scene.
She added 11 people were taken to hospital, and that three died shortly after arrival.
There were no details regarding the assailants.
“Nobody has been arrested. Officers are still on site. They came and shot at people who were having fun,” said Kubheka, commander of the Orlando police station, the Soweto district where the shooting took place.
The bar was in the Orlando district of Soweto, Johannesburg’s largest township, southeast of the capital.
According to Mawela, a high-calibre firearm was used to randomly shoot people in the licensed bar, and the number of cartridges found on the scene indicated it was a group of people who shot at the patrons.
“You can see that every one of those people were struggling to get out of the tavern,” Mawela said.
In a separate incident, four people were killed during a shoot-out in a bar in Pietermaritzburg in eastern South Africa.
The shooting took place towards 08:30pm (18:30GMT) on Saturday and left eight others injured, local police spokesman Nqobile Gwala said.
Two men drove up, entered the bar and “fired random shots at the patrons”, before fleeing, he said. Eight other people were wounded.
“A total of 12 people were shot. Two people were declared dead at the scene and the other two died in hospital,” Gwala said.
The shootings come two weeks after 21 teenagers were found dead in a tavern in the city of East London. The cause of those deaths has not yet been announced by authorities, but the teens were not shot nor crushed in a stampede, according to officials.