CRANS-MONTANA, Switzerland (AP) — Authorities in Switzerland are currently investigating a devastating fire that erupted in a bar at an Alpine ski resort, claiming the lives of approximately 40 individuals and injuring another 115 during a New Year’s celebration.

The majority of injuries, several of which are severe, occurred when flames rapidly engulfed the packed bar just under two hours post-midnight on Thursday in the southwestern part of Switzerland.

Crans-Montana, a resort renowned for its international ski and golf events, saw its vibrant Le Constellation bar transform overnight from a hub of festivity into the backdrop of one of Switzerland’s most harrowing disasters.

Authorities stated on Thursday that determining the exact cause of the fire is still in its early stages, but they have already dismissed the possibility of it being an attack.

Located less than 5 kilometers (3 miles) from Sierre, Switzerland, Crans-Montana is near the site of another tragic incident in 2012, where a bus crash inside a Swiss tunnel resulted in the deaths of 28 people, including many children, from Belgium.

Here’s what we know about the deadly fire:

A frantic attempt to escape

The blaze broke out around 1:30 a.m. Thursday during a holiday celebration inside the Le Constellation bar.

Two women told French broadcaster BFMTV they were inside when they saw a male bartender lifting a female bartender on his shoulders as she held a lit candle in a bottle. The flames spread, collapsing the wooden ceiling, they told the broadcaster.

People frantically tried to escape from the basement nightclub up a narrow flight of stairs and through a narrow door, causing a crowd surge, one of the women said.

A young man at the scene said people smashed windows to escape the fire, some gravely injured, reported BFMTV. He said he saw about 20 people scrambling to get out of the smoke and flames.

Gianni Campolo, a Swiss 19-year-old who was in Crans-Montana on holiday, rushed to the bar to help first responders after receiving a call from a friend who escaped the inferno.

“As we get closer, we see almost dismembered persons lying on the floor, in cardiac arrest. People were also inside trapped, laying on the ground. We saw their clothes melting onto their skin,” Campolo told TF1. “I have seen horror and I don’t know what else would be worse than this.”

The blaze triggered a flashover or backdraft

The Swiss officials called the blaze an “embrasement généralisé,” a French 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.

The injured suffered from serious burns and smoke inhalation. Some were flown to specialist hospitals across the country.

Authorities urged people to show caution in the coming days to avoid any accidents that could require the already overwhelmed medical resources.

Italian and French nationals are among the missing

Thirteen of the wounded were Italian citizens, and another six Italians are unaccounted for, Italy’s ambassador to Switzerland, Gian Lorenzo Cornado, told state-run RAI television.

One of the people missing was Giovanni Tamburi, whose mother Carla Masielli issued an appeal for any news about her son and asked the media to show his photo in hopes of identifying him.

“We have called all the hospitals but they don’t give me any news. We don’t know if he’s among the dead. We don’t know if he’s among the missing,” she wailed. “They don’t tell us anything!”

Three of the wounded were being transported from Switzerland to a Milan hospital, the Italian civil protection agency said.

France’s foreign ministry said eight French people are missing and another nine are among the injured. Top-flight French soccer team FC Metz said one of its trainee players, 19-year-old Tahirys Dos Santos, was badly burned and has been transferred by plane to Germany for treatment.

A top venue for the world’s best athletes

With high-altitude ski runs rising around 3,000 meters (nearly 9,850 feet) in the heart of the Valais region’s snowy peaks and pine forests, Crans-Montana is one of the top venues on the World Cup circuit.

The resort will host the best men’s and women’s downhill racers, including Lindsey Vonn, for their final events before the Milan Cortina Olympics in February.

The town’s Crans-sur-Sierre golf club, down the street from the bar, stages the European Masters each August on a picturesque course.

Dazio reported from Berlin and Leicester reported from Paris. Geir Moulson in Berlin, Graham Dunbar in Geneva and Nicole Winfield in Rome contributed to this report.