A deadly fire broke out during New Year’s celebrations at a Swiss ski resort bar, leaving multiple people dead and injured, authorities said.

Several people were killed and others injured when an explosion ripped through a bar in the luxury Alpine ski resort town of Crans Montana, Swiss police said early Thursday.

"Several dozen people are presumed to have died," Frederic Gisler, police commander in the Wallis canton in southwestern Switzerland, told reporters, adding that around 100 people had been injured, ma...