An explosion at a block of flats in the Swedish city of Gothenburg early on Tuesday sent about 25 people to the hospital.
The Greater Gothenburg Fire and Rescue Service said there was no natural cause behind the explosion. The fire service added there was no gas pipeline in the house.
The Police said they had opened an investigation but had no suspects at the time.
At least three of those taken to hospital were seriously injured, Gotesborgs-Posten reported. The local hospital said three over-60s women were seriously injured.
The fire service said 15 units were on the scene. Eleven ambulances were also in attendance.
Emergency services said several hundred people had been evacuated from the vicinity.
“It’s awkward. There are at least three stairwells that are affected,” said Lotta Molander of the fire service.
The fire service said it was alerted to the explosion just before 5:00am. Jessica, a resident of the block, told a local paper she was awoken at 4.30am by a loud bang.
She said she lives in a low-floor flat but was unable to exit the building by the stairwell, leaving her to descend via the balcony.
The immediate cause of the explosion and fire was unclear. The Nordic country has contended with surging gang crime in recent years, with rival groups employing explosives and fire arms to settle scores.
Axel Josefson, mayor of Gothenburg, said it was a very serious incident due to the location of the block and the number of families affected. “Many Gothenburgers have lost their homes here today,” he said.