JOHANNESBURG (AP) — South African police are investigating the deaths of at least 20 people at a nightclub in the coastal town of East London early Sunday.

It is unclear what led to the deaths of the young people, who were reportedly attending a party to celebrate the end of winter school exams.

Local newspaper Daily Dispatch reported that bodies were strewn across tables and chairs without any visible signs of injuries.

“At this point we cannot confirm the cause of death,” said health department spokesperson Siyanda Manana.

“We are going to conduct autopsies as soon as possible to establish the probable cause of death. The deceased have been taken to state mortuaries,” Manana added.

Police Minister Bheki Cele was on Sunday morning expected to visit the scene.

The owner of the club, Siyakhangela Ndevu, told local broadcaster eNCA that he had been called to the scene early Sunday morning.

“I am still uncertain about what really happened, but when I was called in the morning I was told the place was too full and that some people were trying to force their way into the tavern,” he said.

“However, we will hear what the police say about the cause of death,” Ndevu added.