The bodies were discovered early Sunday morning in Enyobeni Tavern, a popular tavern in the Eastern Cape suburb of Scenery Park.
The victims are mostly between the ages of 18 and 20.
The cause of death is unknown, according to police, but witnesses say the bodies show 'no obvious sign of injury' and appear to have collapsed where they stood.
Some speculate that the death toll could be as high as 22, but this has yet to be confirmed.
According to SABC, four people have been taken to the hospital.
There have been suggestions that the tragedy was caused by a poisonous substance, such as a gas leak, but police have stated that they will not speculate on the cause of death.
They called the scene "horrific," with bodies strewn across the floor, chairs, and tables.
They claimed that families gathered outside calling out the names of their loved ones were not allowed in.
They also stated that photos from the tavern were not suitable for publication.
According to the Isolezwe News, a Zulu-language newspaper, "bodies were everywhere" with no signs of injury.
The incident was reported to police by members of the public, according to Eastern Cape police spokesperson Brigadier Tembinkosi Kinana.
According to police, the circumstances of the deaths are "under investigation," and it is too early to determine the cause of death.
The majority of the people were between the ages of 18 and 20, according to the spokesperson.
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