Twenty people plunged to their deaths yesterday when a cable car to an Alpine observatory came unhooked and plummeted 80 m (265 feet), the worst such accident on record in France.
Officials said all of the casualties were French and most were employed at the Plateau de Bure Interferometer, an astronomical centre perched above the town of SaintEtienne-en-Devoluy, about 50 km (30 miles) south of Grenoble.
The accident happened as the cable car began a 20-minute voyage in fine weather toward the 2,700 m (8,880-foot) Pic de Bur, where the observatory is located.
The regional prefect, Ms Remi Caron, said the cable car had come unhooked for no known reason shortly after it began its ascent, sending the passengers plummeting to their deaths.
A judicial inquiry was opened to determine the cause of the accident. Initial reports had said the cable snapped as the cabin had almost reached the upper station.
Mr Jean-Charles Simiand, an official from the French cable car association, said the doomed car was built in the 1980s and had
undergone a safety inspection last year.
Mr Simiand said the cable itself also undergoes frequent inspections. "France has the tightest controls worldwide," he added.
The Transport Ministry said its staff had not taken part in the checks as the cable car was privately-run and was not open to the public.
Local officials initially put the death toll at 21 but later said 20 bodies had been recovered from the wreckage and transported to the local church.
Weeping, Mayor Jean-Michel Bernard said: "We owe it to the families to find out why this happened." The small village has only 545 residents.
Mr Bernard broke into tears as he told a news conference: "The mountain is mourning."
"Twenty people have died. It is terrible for the mayor of a village of 500 to see that," he said.
Some 100 gendarmes of the mountain rescue squad ferried the bodies down by helicopter to the local church.
Four of the victims were employed by sub-contractors to France Telecom. About a dozen were employed by the public works company BTP and several others worked for a local cleaning firm.
President Jacques Chirac said the tragedy "has plunged the entire country into mourning" and sent his chief of staff to the site with the Interior Minister, Mr Jean-Pierre Chevenement, and the Labour and Solidarity Minister, Ms Martine Aubry.
"This is a terrible accident," Mr Chevenement said earlier in Paris. "Our hearts go out to the victims and their families."
The astronomical observatory, run by the Franco-German company IRAM, is connected to the village of Saint-Etienne-en-Devoluy by the cable car and is closed to tourists.
The village is not far from the Alpine resort of SuperDevoluy.
The accident was the worst recorded in France since 1960, the year when such records began.
In a previous accident in February 1998, at Cavalese in Italy, 20 people died when a US military plane severed a cable car cable. The world's most serious cable car crash killed 42 in 1976, also in Cavalese.
The mountain-top Pic de Bur observatory consists of five antennas used by astronomers to observe cosmic radio waves.
The site is considered exceptional by scientists because there is little precipitation, making for clear skies.
The State Prosecutor, Mr Michel Selaries, said there may have been "serious machinery failures", and that he would open an inquiry into suspected manslaughter after receiving a report by a technical expert.
"The car fell, the cable did not snap," he said.
Mr Chevenement said the disaster was puzzling because the car did not get unhooked from the cable as is the case in most cable car accidents, and the cable did not appear to have snapped.
Technical documents say the car carried loads of up to seven tonnes during the observatory's construction.