A young woman is reported to be in a critical condition with a further four people sustaining serious injuries.
“It was constructed audience platform which gave way,” said Marie Lindqvist at Stockholm Globe Arenas.
The stage section collapsed during a concert by DJ Aviccii and the evening’s second concert was cancelled after the accident.
The 20 injured people were taken to Karolinska Hospital in Solna, St. Göran’s Hospital, Karolinska Hospital in Huddinge and Stockholm South General Hospital.
The leader of the medical team, Daniel Ekberg, confirmed that one woman sustained life threatening injuries and four serious injuries. The remaining 15 people sustained minor injuries.
“For example it concerns spinal injuries,” he said.
When the accident occurred there were around 7,000 people inside the arena.
The police have confirmed that they have opened a preliminary investigation into criminal negligence.
Marie Lindkvist said that the concert was completed and that the atmosphere was calm, with all those in need receiving medical attention.
The second concert planned for Friday evening was however cancelled after the accident and it remains unclear what will happen with Saturday’s programme.
Neither the concert organiser or Stockolm Globe Arenas was willing to speculate over possible causes for the accident.
“That will have to be revealed by the police investigation,” said Kalle Pettersson at the promoter STG Live.
The platform which collapsed had been built by an external supplier and had been constructed specifically for this event.
“The firm has followed existing norms and regulations,” Pettersson claimed.
He was unable to specify exactly how many people were on the platform at the time, but underlined that the capacity had not been breached.
The decision to continue the concert was taken in cooperation with the police and arena management.