At least 22 people have died from unexplained causes in a pub in the South African city of East London. The incident was reported in the early hours of Sunday morning and the police had launched a forensic investigation, Eastern Cape Province Police Commissioner Nomthetheleli Mene told public broadcaster SABC.

“Three of the injured have died in hospital and two are still in very critical condition,” Weziwe Tikana-Gxothiwe, head of the provincial government’s security service, later told local television. According to Police Minister Bheki Cele, the dead were between the ages of 13 and 17. This is reported by the news site “news24”. The police had previously spoken of 18 to 20-year-olds.

The police initially did not want to provide more detailed information about the cause of the incident. According to reports from emergency services, there was a crowd in the small tavern. Some eyewitnesses suspected poisoning of the pub visitors.

The local newspaper DispatchLive reported: “The bodies are lying on tables, chairs and on the floor with no obvious signs of injury.” lay on the floor of the restaurant.

“22 bodies were found on the ground. No open wounds, no nothing. We don’t know if they were poisoned or if something else happened,” said provincial transport ministry spokeswoman Unathi Bingose. “It’s hard to believe there was stampede as none of the victims have visible open wounds,” he told AFP over the phone.

“We will start the autopsy immediately so we can determine the probable cause of death,” he told Reuters as coroners continued their work at the cordoned-off crime scene at the Enyobeni Tavern.

Police officers were seen on local television trying to calm a crowd outside the nightclub. “Parents whose children have not slept at home have gathered here,” Binqose said. Apparently it was a celebration after school-leaving exams. East London is almost 1000 kilometers south of Johannesburg on the Indian Ocean.