Dozens of people are presumed dead and 100 are injured after a fire at a bar in the Swiss Alps during New Year's Eve celebrations.
Police say the blaze broke out at Le Constellation bar, in the Alpine ski resort municipality of Crans-Montana, about 1.30am today (11.30am AEDT).
"Several tens of people" are presumed dead and about 100 injured, most of them seriously, Valais Canton police commander Frédéric Gisler said at a press conference tonight.
READ MORE: Monsoonal deluge continues to batter northern Queensland
Work is under way to identify the victims and inform their families but "that will take time and for the time being it is premature to give you a more precise figure", Gisler said.
Beatrice Pilloud, attorney general of the Valais Canton, said it was too early to determine the cause of the fire. Experts have not yet been able to go inside the wreckage.
"At no moment is there a question of any kind of attack," Pilloud said.
Officials called the blaze an "embrasement généralisé", a firefighting term describing how a blaze can trigger the release of combustible gases that can then ignite violently and cause what English-speaking firefighters would call a flashover or a backdraft.
"This evening should have been a moment of celebration and coming together, but it turned into a nightmare," said Mathias Rénard, head of the regional government.
The injured are so numerous that the intensive care unit and operating theatre at the regional hospital quickly hit capacity, regional councilor Mathias Rénard said.
In a region busy with tourists skiing on the slopes, the authorities have called on the local population to show caution in the coming days to avoid any accidents that could require medical resources that are already overwhelmed.
Rescue efforts were ongoing and the area has been closed off with a no-fly zone in place over Crans-Montana, police said.
'We are devastated'
Helicopters and ambulances rushed to the scene to assist victims, including some from different countries.
"We are devastated," Frédéric Gisler, commander of the Valais Cantonal police, said during a news conference.
Earlier, police spokesperson Gaëtan Lathion said "more than a hundred people were in the building, and we are seeing many injured and many dead".
A reception centre and helpline have been set up for impacted families, Lathion said.
"We're just at the beginning of our investigation, but this is an internationally renowned ski resort with lots of tourists," Lathion said.
The community is in the heart of the Swiss Alps, just 40 kilometres north of the Matterhorn, one of the most famous Alpine peaks, and 130 kilometres south of Zurich.
Crans-Montana is one of Switzerland's most exclusive locales, famed for its year-round sunshine, which it owes to its position on a south-facing plateau in the Rhone Valley.
The ski resort is about two hours east of Geneva and visited by 3 million tourists each year, mainly from other parts of Switzerland, Italy and France.
The highest point of Crans-Montana, with a population of 10,000 residents, sits at an elevation of nearly 3000 metres, according to the municipality's website, which says officials are seeking to move away from a tourist culture and attract high-tech research and development.
The municipality was formed only nine years ago, on January 1, 2017, when multiple towns merged. It extends over 590 hectares from the Rhône Valley to the Plaine Morte glacier.
Tourists are drawn by its understated glamour, with high-end shopping and fine dining as well as extensive ski slopes and a lively apres-ski scene.
With a small population, the area is said to have a close-knit community as well as being a low-key place for celebrities to go skiing, golfing and dining.
- Reported with Associated Press and CNN