There ain't no party like a bunker party.

Twenty-five people were hospitalized with carbon monoxide poisoning after taking part in an illegal rave party that was powered by two diesel generators in Norway over the weekend, authorities said.

They were among some 200 partygoers in their 20s and 30s who gathered in a concrete bunker Saturday night in Oslo for an event that had been announced on closed social media pages.

Police raided the party early Sunday morning after officers ran into a group of confused young people at a nearby park. Emergency personnel was called and found at least seven people unconscious in the bunker, local officials said.

Five of those who were taken to the hospital were initially listed in critical condition, including two officers who were first on the scene, Norwegian news agency NTB reported. Two of them were released from intensive care Monday and the others were also expected to survive, according to NTB.