Champion sailor Florence Arthaud, Olympic gold medalist swimmer Camille Muffat and Olympic boxer Alexis Vastine were among those killed when two helicopters filming the survival series "Dropped" crashed into each other in the rugged mountains of north west Argentina, local officials said.

"Apparently, the two helicopters collided as they were filming. There are no survivors," provincial spokesman Horacio Alarcon told AFP.

He said the weather conditions were good and the cause of the crash was unknown.

Fotos del accidente de haces unas hora @C5N @infobae @gustsaldana @telefenoticias pic.twitter.com/IHMgyDOS3N

— Maximiliano Dopazo (@JeagerDopazo) March 9, 2015

Argentine media showed the wreckage of the two helicopters in flames on the dry scrubland, in La Rioja province.

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

(Olympic gold medalist Camille Muffat celebrates winning gold in London in 2012. AFP)

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 a top swimmer at the London Olympics in 2012, bringing home three medals, including the gold in the 400-meter freestyle.

(Aerial picture taken on October 23, 2007 shows the French skipper Florence Arthaud aboard the monohull "Deep Blue". AFP)

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

Reaction to the tragedy and tributes to the victims poured in on Tuesday.

A statement from the Elysée Palace said President François Hollande learned about the deaths "with immense shock and emotion" and expressed "condolences and support" to the victims' friends and families.

"Immense sadness over this tragedy. The whole of France is in mourning today. Thoughts go to the families of the victims," tweeted French Prime Minister Manuel Valls.

Argentine : peine immense devant ce drame. C'est toute la France qui est en deuil ce matin. Soutien aux familles des victimes. MV

— Manuel Valls (@manuelvalls) March 10, 2015

The minister for sport Thierry Braillard said: "French sport is in mourning. We have lost three great champions".  

'Complicated conditions' 

"Dropped," which was to air on French television channel TF1, involved eight sports stars being dropped into inhospitable environments for an adventure- and survival-themed reality show.

The other stars participating in the show were swimmer Alain Bernard, cyclist Jeannie Longo, footballer Sylvain Wiltord, snowboarder Anne-Flore Marxer and figure skater Philippe Candeloro.

None of them were among the victims.

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

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.

'Extreme' landscape 

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

The provincial government said the crash happened in the Quebrada del Yeso gorge.

One of the helicopters was provided by the provincial government and the other by the police force in the neighboring 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, a police source told AFP.

"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.

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