About 40 people are believed to have been killed and 100 injured after a fire tore through a crowded bar during a New Year’s Eve party in the Swiss ski resort of Crans-Montana, according to the Italian foreign ministry.

The Italian foreign ministry said information from Swiss police indicated about 40 deaths, but Swiss police declined to give a specific ‍figure.

Police said the explosion took place at about 1.30am local time in a bar called Le Constellation, which is popular with tourists, as revellers rang in the new year.

The Department of Foreign Affairs is aware of the incident and stands ready to provide consular assistance

The Irish Embassy in Switzerland said it is “monitoring the situation” and for “any Irish citizen in need of consular assistance” to call the Embassy on +41 (0) 31 350 0380 or +353 (0) 1 408 2000.

Two French women who said they were in the bar told France’s BFM TV that they saw the fire start in the basement section of the club after a bottle containing “birthday candles” was held up too close to the wooden ceiling.

“The fire spread across the ceiling super quickly,” one of the two women told BFM TV. The pair said they were able to climb a narrow staircase to the ‌ground floor as panic broke and escape the building. Minutes later, the fire had reached the ground floor too, they said.

It was not immediately possible to verify their account from other sources. Video footage, verified by Reuters, showed fire spreading from the building ⁠with people outside the club, some running and screaming.

Italy’s ambassador to Switzerland, Gian Lorenzo Cornado, told Sky TG24 local authorities had told him the blaze ‌was started ​by ‍someone letting off a firework inside the bar that set fire to the ceiling.

Earlier, Gaetan Lathion, a police spokesperson in Wallis canton in southwest Switzerland, told AFP there had been “an explosion of unknown origin”.

“More than a hundred people were in the building, and we are seeing many injured and many dead,” he said.

“At the moment we are considering this a fire and we are not considering the possibility of an attack,” prosecutor Beatrice Pilloud ⁠told a press conference on Thursday morning, adding that authorities had opened a full investigation.

Some of the victims ‌are ​from ‍other countries, said Stephane Ganzer, head of security for the Valais canton.

Speaking during the press conference, Mathias Reynard, president of the canton of Valais, said what should have been a moment of celebration “turned into a nightmare”.

The injured have been taken to local hospitals, as well as facilities in Lausanne, Geneva and Zurich. Some may have been foreign nationals as the area is a popular location for tourists.

From the scene on Thursday morning, Romaine Morard, a journalist for the newspaper, described “a smell of burning still in the air”.

Rescuers and firefighters work at the site of an explosion that ripped through a bar in Crans-Montana. Photograph: MAXIME SCHMID/AFP via Getty ImagesRescuers and firefighters work at the site of an explosion that ripped through a bar in Crans-Montana. Photograph: MAXIME SCHMID/AFP via Getty Images

The area has been closed off, and a no-fly zone has been imposed over Crans-Montana, police said, adding that the cause of the fire remained unclear.

The tragedy was the result of an accident and was not a terror attack, officials said on Thursday morning. There were media reports of an explosion at the scene, but the fire department said this was caused by the blaze rather than the other way around.

There were unconfirmed reports that fireworks, or pyrotechnics, might have been a cause.

Images published by Swiss media showed a building in flames, and emergency services nearby.

A reception centre and helpline (0848 112 117) have been set up for impacted families, Mr Lathion said. “We’re just at the beginning of our investigation, but this is a internationally renowned ski resort with lots of tourists,” he added.

Crans-Montana is a municipality in the district of Sierre in the canton of Valais in Switzerland, 40km (25 miles) north of the Matterhorn.

It is one of the top race venues on the World Cup circuit in Alpine skiing and will host the next world championships over two weeks in February 2027.

Crans-Montana is also a popular hiking area and a premium venue in international golf. – Agencies