“Several dozen” people are presumed dead, and others were injured when an explosion ripped through a bar at the luxury Alpine ski resort town of Crans Montana, Swiss police said early on Thursday.

“There has been an explosion of unknown origin,” Gaetan Lathion, a police spokesman in Wallis canton in southwestern Switzerland, told AFP.

“There are several injured, and several dead.”

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

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

“The intervention is still ongoing,” he said.

- Agence France-Presse