At least 25 people have been poisoned by carbon monoxide at an illegal rave in a bunker in Norway.
Some 200 people attended the event in Oslo, which used portable diesel generators to power the lighting and sound systems.
Police discovered the event after they came across a group of confused young people in the park where the bunker lies.
Emergency services found seven people unconscious in the bunker.
Five people, including two police officers, were taken to hospital in a critical condition, Norwegian news agency NTB said.
Two of the five people are no longer in intensive care.
The company that owns the bunker described the illegal rave as a "serious break-in" and said the company did not bear any responsibility, Norway’s VG newspaper reported.
The entrance to the bunker was previously closed with double-reinforced concrete. However, it was reopened by new owners and only secured with wooden boards.
The organisers said the diesel generators were in a room with ventilation, but several partygoers told Norwegian media that they had to go outside several times to breathe fresh air.
