Witnesses reported seeing staff at the Le Constellation bar carrying so-called fountain candles atop bottles of champagne, and questions have also arisen about a foam material used to soundproof the ceiling of the basement where revellers danced.

Beatrice Pilloud, chief prosecutor of Valais, the canton that is home to the bar in the upscale ski resort of Crans-Montana, said that available indications were that the fire started because the sparklers got too near to the ceiling.

"From there, a rapid, very rapid and widespread blaze ensued," she said on Friday afternoon.

Further investigations will show whether anyone faces criminal liability over the fire, Pilloud said.

Police arrived quickly at the scene according to local residents, but the fire burned victims so severely that investigators said they would need days to identify the bodies.

So far, officials have only identified a teenage Italian international golfer, Emanuele Galeppini. According to two people familiar with the investigation, some of the victims may be under 16.

Local residents said the bar was popular with young people and the Swiss government said many of the dead were likely youths. Beer and wine can be drunk from age 16 in Switzerland.

One of the bar's owners, Jacques Moretti, told the Tribune de Geneve newspaper that Le Constellation had been checked three times in 10 years and that everything was done according to the rules. Reuters was not immediately able to contact the bar's owners for comment.

Stephane Ganzer, head of security in Valais, said the investigation would determine if the bar had undergone its annual building inspections, but that the town had not raised concerns or reported defects to the canton.

Grieving residents continued paying their respects to the victims of the blaze on Friday, leaving flowers and tributes nearby, even as police began reopening the area around the cordoned-off bar in the heart of the wealthy mountain town.

One of them, Ashley Hauri, 23, said just before the fire broke out she had been on the verge of going to Le Constellation to catch up with friends. Ultimately, she decided against it.

Six of her former co-workers ranging in age from their 20s to their 40s were inside when the blaze erupted, she said. Two of them ended up in hospital; the other four are still missing.

"I was really shocked," said Hauri, who immediately tried to contact her friends. "But I had no answers, and I was really scared and panicked because I wanted to do something."

Popular

New criminal code requires public oversight, minister says

Surviving via 'VCS': Indonesians turn to virtual sex work amid COVID-19

Actor Will Smith appears to have his front teeth knocked out by singer Jason Derulo