A British woman and her 22-year-old son have been killed in an avalanche while skiing in France.

The mother, 54, and son, who have not been named, had been skiing off-piste near the Swiss border when they were buried by an avalanche at about 3:30pm local time (14:30 GMT) on Thursday.

The deceased were part of a group of five people from the same family with a guide they had known for years.

Local media say they were not wearing devices used to locate survivors.

The avalanche began near the Saint-Gervais resort at an altitude of around 2,300 metres (7,546 feet) and travelled around 400 metres, local authorities said. It may have been triggered by another party of skiers at a higher altitude, they added.

The two victims were found after around five hours of searching by 20 first responders and two helicopters, said Bonneville prosecutor Karline Bouisset in a statement.

They were found buried and deceased, Ms Bouisset added.

The guide accompanying the family was reportedly wearing an avalanche beacon, but none of the family were. The devices are used to locate buried survivors of avalanches.

Separately, in Isère, a 31-year-old man was killed after falling some 500 metres in the Écrins Massif.

An avalanche killed six people at the Armancette glacier, near Mont Blanc in south-eastern France, in April.

Around 110 people are caught in avalanches every year in France, leading to about 30 deaths. (BBC)

Rescue police officers takes part in a search and rescue exercise for avalanche victims in the French Alps