France mourns sports stars killed in Argentine crash

France was plunged into mourning Tuesday after the deaths of three sports stars, including an Olympic champion swimmer and one of the world's best sailors, in a helicopter crash while filming a reality TV show in Argentina.

Champion sailor Florence Arthaud, Olympic gold medallist swimmer Camille Muffat and Olympic boxer Alexis Vastine were among 10 people killed when two helicopters filming the survival series "Dropped" smashed into each other in the rugged mountains of La Rioja province, local officials said.

"The whole of France is in mourning this morning," said Prime Minister Manuel Valls.

Rioja provincial spokesman Horacio Alarcon told AFP there were no survivors in the crash, which happened in good weather conditions on Monday.

Local media showed the wreckage of the two helicopters in flames on the dry scrubland in the northwestern Argentinian province.

It was the worst accident in the history of reality television.

Alongside the three sports stars, five French TV crew members and two Argentine pilots died in the crash, a police source said.

Arthaud, 57, was considered one of the best sailors in the world, a woman who conquered what had been a strictly male-dominated sport. Her titles included the 1990 Route du Rhum, the most prestigious race to cross the Atlantic solo.

Muffat, 25, was one of the top swimmers in French history, winning three medals at the London Olympics in 2012, including gold in the 400-metres freestyle.

- 'Immense sadness' -

She shocked the sporting world in June 2014 by announcing her sudden retirement at the age of 24, exhausted by the long hours of training in the pool.

Vastine, 28, won a bronze medal at the Beijing games in 2008 in the light welterweight category.

President Francois Hollande led the tributes, saying the "brutal death of our compatriots is an immense sadness".

Muffat's former trainer Fabrice Pellerin told French radio station RTL: "What's hard is to reconcile the image I have of Camille, who was unsinkable, with what happened."

"To have in my head this strong girl, full of the joys of life, and then everything stops. I have known her since she was 13 so it's like I've lost someone in my family."

"Dropped" involved eight sports stars being dropped into inhospitable environments for an adventure- and survival-themed show.

- Production halted -

Fellow contestant, former France and Arsenal football star Sylvain Wiltord, said on Twitter: "I am sad for my friends. I am horrified. I'm speechless. I don't want to say anything."

The other stars taking part in the show -- none of them hurt in the accident -- were swimmer Alain Bernard, cyclist Jeannie Longo, snowboarder Anne-Flore Marxer and figure skater Philippe Candeloro.

"We've got people who are way beyond average for their record of achievements, that's clear," the show's presenter Louis Bodin said in a recent interview with RTL.

"And we can tell that on the ground, on all kinds of terrain, that they've got the ability to adapt... Of course, the logistics, the conditions are sometimes a little complicated," he said of the show that was to air on French television channel TF1.

Production company Adventure Line Productions (ALP) said it was "shattered" by the tragedy. It said it would "of course" immediately stop production and repatriate the teams.

ALP was involved in another French reality TV accident in 2013, when a contestant in survival show "Koh-Lanta" died of a heart attack during filming in Cambodia and a doctor on the programme then committed suicide.

French prosecutors opened a manslaughter investigation into the accident -- standard procedure in France when a national dies abroad.

The Rioja provincial government said a cast and crew of around 80 people, mostly French nationals, had descended on the area to film the series.

Shooting began in late February in Ushuaia, at the southern tip of South America in the glacial terrain of Patagonia.

It then moved to La Rioja, whose scenic mountain landscapes are popular with tourists.

The crash happened around 5:00 pm (2000 GMT) near the town of Villa Castelli, about 1,100 kilometres (700 miles) north of the capital Buenos Aires, said provincial security secretary Cesar Angulo.

One of the helicopters was provided by the provincial government and the other by the police force in the neighbouring province of Santiago del Estero.

Police and firefighters were still working to recover the victims' bodies when night fell, using floodlights to illuminate the area.

"It's been four hours since the collision and (the wreckage) is still on fire. There's smoke rising from the helicopters," said a police source at the scene.