Four skiers were killed and another injured in an avalanche in the French Alps on Friday and their guide was held for questioning, authorities said.

The group of six people was on a ski touring expedition in an off-trail area near Entraunes, close to the Italian border in the southern Alps.

The identities of the skiers were not immediately released. Prosecutor Jean-Michel Pretre of Nice said in remarks shown on French television that they were "seniors," all with experience in backcountry skiing.

He said the guide knew the area well.

A judicial inquiry was opened into manslaughter and involuntary injury, and the guide was taken in for questioning, the prosecutor said.