GENEVA (AFP)

Dozens are presumed dead after a fire ripped through the luxury Swiss ski resort of Crans-Montana as young revellers rang in the new year Thursday, with witnesses describing scenes of "panic."

Horrified bystanders told of people trying to break through the windows to escape, as others, covered in burns, poured into the street.

Police, firefighters, and rescuers rushed to the popular resort, which is set to host the Ski World Cup from January 30, after the fire broke out in the early hours of New Year's Day.

Frederic Gisler, police commander in the Wallis canton in southwestern Switzerland, told reporters that "several dozen people are presumed to have died," while around 100 people had been wounded, many of them seriously.

Authorities said they were still investigating the causes of the fire, which erupted shortly before 1:30 am, but said they did not believe it had been caused by an "attack."

The emergency unit at the main hospital in the Wallis was full, with the injured being transported to various hospitals across Switzerland.

More than a dozen victims had been transported to the Zurich University Hospital in northern Switzerland, while at least 22 people suffering from serious burns had been taken to the main hospital in Lausanne, and six had been taken to Geneva, the Keystone-ATS news agency reported.

Guy Parmelin, who took over the Swiss presidency on Thursday, decried a "terrible tragedy."

"What was meant to be a moment of joy has turned the first day of the year in Crans-Montana into a day of mourning affecting the entire country and beyond," he said on X.

Swiss authorities told reporters that it was too early to provide an exact number of victims.