A fire erupted at a bar in the luxury Alpine ski resort town of Crans-Montana early Thursday, killing dozens of people and injuring over 100, Swiss police said, prompting authorities to cordon off the area and impose a no-fly zone as emergency operations continue.

The blast occurred during New Year celebrations at Le Constellation, a bar popular with international tourists, shortly after midnight. At the time of the blast nearly 100 people were inside the bar.

'Several dozens' feared dead

"Several dozens" of people are presumed dead, with more than 100 injured after fire ripped through ski resort bar, Swiss police said in a news conference.Most of the injured have "significant" injuries with severe burns.Some 10 helicopters, 40 ambulances and 150 responders were sent to the scene. The emergency operation will continue into the coming days, said authorities.The Italian foreign ministry, citing Swiss police, say they believe around 40 people have died. The ministry added the victims could not be immediately identified because of the severity of their burns, Reuters reports.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 were so numerous that the intensive care unit and operating theater at the regional hospital quickly hit full capacity, Rénard said.

'No question of any attack'

Beatrice Pilloud, prosecutor-general, Valais canton, said an investigation is under way "to identify the circumstances which caused this dramatic situation to occur".She said "currently we are favouring a fire and at no time is there question of any attack", adding out of respect for the families she cannot say more at this time.Police have also confirmed that the incident is not being treated as terror related.

Multiple nationalities involved

The region’s head of security said the incident involved people of several nationalities, though no further details were shared. Pilloud said efforts were ongoing to identify the victims and return their bodies to families as quickly as possible.

“To do that there is significant work which needs to be carried out. And this significant work will require the closure of the district.”

Area sealed, no-fly zone imposed

In a brief update, police said the area around the bar remains completely cordoned off, with a major emergency response involving numerous police, fire and rescue teams.Authorities have also declared a no-fly zone over Crans-Montana as rescue and investigation efforts continue, Reuters reported.Images and videos published by Swiss media and on social platforms show flames engulfing part of the building, with firefighters and rescue teams deployed nearby.