At least four people have died and nine others were injured in an avalanche in the French Alps, Interior Minister Gerald Darmanin said on Sunday.

The four caught in the avalanche were backcountry skiing in the mountains and have not been identified yet.

French President Emmnauel Macron wrote on Twitter that rescue workers were continuing to search for further casualties and that his thoughts were with the victims and their families.

The news comes a day after Swiss authorities rescued a group of hikers who found themselves trapped in a snowslide in the Swiss Alps.

What we know so far

The incident happened in the middle of the day at the Armancette glacier, at the altitude of around 3,500 meters (11,500 feet). The glacier is located in the Haute-Savoie region, some 30 kilometers (almost 20 miles) southwest of Chamonix.

Chamonix, the small town at the base of the Mont Blanc, is prime vacation spot over France's long Easter weekend.

Emmanuel Coquand, a spokesperson for the local authorities of Haute-Savoie, said the avalanche was extensive.

The local France-Bleu radio station put the size of the avalanche at 1,000 meters (3,280 feet) long and 100 meters (328 feet) wide.

Two helicopters were sent in to help in the search, the station said, quoting the local prefecture in Thonon.

Experts say avalanche activity could increase in coming years because of climate change.