Around 100 people were also injured in the fire that broke out during New Year`s celebrations in the municipality of Crans-Montana, authorities said.

People embrace near the site of the fire.Denis Balibouse / Reuters

At least 40 people are dead and more the 100 others were severely injured after a fire broke out during a New Year`s Eve celebration at a bar in a Swiss Alps resort, authorities said Thursday.

Calling it an "unprecedented tragedy," Valais canton police commander Frédéric Gisler warned the death toll could rise because many of the injured are in critical condition.

Meanwhile, Gisler said at a news conference, "the priority will be to identify those who lost their lives."

Swiss President Guy Parmelin said that many of the victims were young people and the victims include Swiss residents as well as tourists from neighboring countries and elsewhere.

"Behind these numbers are faces, names, families, destinies brutally interrupted," Parmelin said at the press conference.

The new year was less than two hours old when the fire that devoured the Le Constellation in the town of Crans-Montana was first reported around 1:30 a.m. (7:30 p.m. ET Wednesday), Gisler said.

Investigators are still probing the cause of the blaze. But Beatrice Pilloud, the Valais canton attorney, said they don`t believe the fire was caused by an explosion, although the "main and working assumption is that a general fire caused an explosion."

"At no moment is there a question of any kind of attack," said Pilloud. "An investigation has been launched, not against anyone, but to shed light on the circumstances surrounding this tragic fire."

Pilloud declined to speculate on eyewitness accounts from The Associated Press and the French broadcaster BFMTV suggesting the fire may have sparked by festive sparklers that set a wooden ceiling ablaze.

But Axel Clavier, a 16-year-old from Paris who survived the fire, told the AP he saw waitresses in the bar with Champagne bottles with sparklers just before the inferno erupted.

"I`m still in shock," said Clavier, who told the AP one of his friends died and "two or three were missing."

Firefighters arrived on the scene within minutes, and by 5 a.m., all of the injured were receiving treatment and being taken to hospitals around the country, said Mathias Renard, who is president of the state council of the Valais canton.

NBC News verified footage posted to social media that showed the building ablaze, with thick smoke billowing into the air as crowds gathered around and some people ran toward the scene. Screaming could be heard in the background.

Another video posted to TikTok showed emergency services on scene in the aftermath of the blaze and the area sealed off with police tape.

???????????????? Des personnes prises au piège par les flammes dans le bar de Crans-Montana tentent désespérément de s’échapper par la seule issue, qui est bloquée. (témoins) pic.twitter.com/aBQXtKRME9

— SuisseAlert (@SuisseAlert) January 1, 2026

Martin Meul, a reporter for Swiss German-language daily newspaper Blick, told NBC News` British broadcasting partner Sky News that he was in a restaurant next door to Le Constellation when the fire broke out.

"I went out to see what happened, and a lot of people were screaming and it was horrible," he said. "A lot of people were trying to escape through the main door. I saw a lot of people on the floor, and I think these people were dead."

Parmelin, whose first day in office was on Thursday, wrote on X that the government`s "thoughts go to the victims, to the injured and their relatives, to whom it addresses its sincere condolences." What was meant to be a moment of joy turned into one of mourning, he added.

Out of respect for victims` families, Parmelin delayed a traditional New Year`s address to the nation meant to be broadcast Thursday afternoon, Swiss broadcasters SRF and RTS reported.

Italy`s foreign ministry said in a statement that many of the victims could not be immediately identified because of the severity of their burns.

In a post on X, the U.S. Embassy in Switzerland urged American citizens in the country to "notify family and friends of their safety."

Earlier, Rénard said the sheer number of victims quickly overwhelmed the intensive care unit and operating theater at the regional hospital, forcing authorities to transfer patients to medical facilities further away.

A no-fly zone was established over Crans-Montana, which sits in the region of Valais, around two hours from the Swiss capital of Bern, to make it easier to evacuate the injured by air, local police said.

Dozens of people are feared dead and hundreds more injured. Maxime Schmid / AFP - Getty Images

The Swiss authorities also established a reception center and helpline for relatives and loved ones of the dead and injured.

Fatal bar fire in the Swiss Alps

Graphic: Joe Murphy / NBC News

Crans-Montana is located in the heart of the Swiss Alps, just 25 miles north of the Matterhorn.

At the end of this month, Crans-Montana is scheduled to host an international speed skiing championship called the Audi FIS Alpine Ski World Cup.