A four-year-old British girl has been found alive underneath the bodies of her family hours after a gunman opened fire on their car in the French Alps.

The girl lay undiscovered as police waited for forensic experts to arrive at the scene.

The bodies of a man and two women - reportedly the girl's mother, father and grandmother - were in the British-registered BMW, which was riddled with bullets.

A seven-year-old girl was discovered lying on the road nearby in a critical condition, while a male cyclist, who had also suffered gunshot wounds, was found dead close to the car. But the four-year-old remained undiscovered under her mother's body for up to eight hours, according to reports.

Public prosecutor Eric Maillaud said she was "terrorised, immobile, in the midst of the bodies". He said: "As soon as the first forensics began, we were able to open the vehicle, and it was at that moment we discovered the little girl, around four years old, that nobody had seen, because she hadn't moved, completely in shock and completely frozen."

The BMW was discovered surrounded by spent bullet cartridges on Wednesday afternoon in a car park on the outskirts of a forest near Lake Annecy, a picturesque region popular with tourists. Mr Maillaud said 15 cartridges were found around the car and a "very large number" of shots had been fired.

French officials said the vehicle was owned by a UK national who was staying at a nearby campsite, believed to be Le Solitaire du Lac in the Saint-Jorioz area. Mr Maillaud said the man checked into the site with two women and two young girls, adding: "The owner of the vehicle was British and he was the person who identified himself to the campsite. He is presumed to be a victim and was accompanied by two women and two little girls. We can assume it's a family, although it is yet to be proved. We have been taking evidence, including DNA, which will be sent to the British authorities for confirmation."

Mr Maillaud, who described the scene as being like something from a film, said the two dead women were found in the back seat of the car and the dead man was in the front. He said the critically injured seven-year-old was taken to the nearby Grenoble University Hospital where her condition has stabilised following emergency surgery.

The cyclist found dead near the car worked for a firm based some miles away. His wife, worried when he did not return from his cycle ride, alerted the authorities, without making a link to the killings. She went to a local police station with a photograph of her husband. Officers quickly made the link and her husband was identified as the fourth victim. He found himself in the wrong place at the wrong time, Mr Maillaud said.

The Foreign Office said that the British Embassy's deputy head of mission in France was at the scene of the shooting. "She is liaising with the local authorities and police to get more information," a spokesman said.