Police say several people have been killed in an explosion at a ski resort bar in the Swiss Alps in the canton of Valais.

Police said in a statement to the BBC on Thursday that the explosion occurred at the Le Constellation bar at around 1:30am local time.

Swiss media reported that the bar caught fire after the explosion.

The BBC reported that video footage circulating on social media, which has not been verified, showed the bar on fire. The New Year’s celebration was taking place there at the time of the incident.

Crans-Montana is a luxury ski resort. It is located in the heart of the Swiss Alps. It takes about two hours to get there from the country’s capital, Bern.

Swiss media outlet Blick quoted a police spokesman as saying that more than a hundred people were in the bar at the time of the explosion.

Police said “several” people had been killed, but did not give a specific number. Major emergency measures are reportedly being taken to deal with the situation. A large number of police, firefighters and rescue services have gathered at the scene.

The scene has been completely cordoned off. A “no-fly zone” has been declared over the crater.

Police are expected to announce the exact number of people killed and their nationalities shortly.

Local media reports have suggested that the explosion was caused by pyrotechnics used to create fire and smoke on stage, but this has not been confirmed.