One person was killed and another seriously injured Sunday in an explosion on a beach on the western French island of Groix, where they were camping, local media reported, according to dpa.
The blast took place as a group of friends in their twenties, who had come from the mainland for a night, were gathered around a camp fire, the regional Ouest France newspaper reported.
A 26-year-old man was killed outright and another was rushed to hospital with serious facial and leg injuries, the paper reported.
Eight others were treated for shock.
The cause of the blast was unknown but one of the hypotheses being explored was that stray World War II ordnance was lodged under the sand, at the spot where they built the fire.
Bomb disposal experts were dispatched to the scene.