“Emergency responders are still at work” and the toll is “provisional”, Darmanin wrote on Twitter, adding that he was “thinking of the victims and their loved ones.”

Nine people apart from the four killed were “involved” in the avalanche, which measured 1,000m long by 100m wide, the prefecture of the Haute-Savoie department told AFP.

The people involved, whose identities have not yet been determined, were hiking near the Glacier d’Armancette as part of one or several groups.

No avalanche warning had been issued for the region by weather authority Meteo France.

“We’re thinking of (the victims) as well as of their families,” President Emmanuel Macron wrote on Twitter.

“Our emergency services have been mobilised to find those still trapped in the snow.”

Emergency responders deployed a helicopter as well as specialist mountain rescue dogs to the scene and are still combing the area, although the prefecture warned that a further avalanche cannot be ruled out.

Two brothers died in an avalanche on the same glacier in 2014, both experienced climbers in their 20s.