Three French athletes have been killed in a helicopter crash in Argentina that claimed a total of ten lives. They were taking part in the filming of French reality show Dropped, in which celebrities are taken to remote locations and have to fend for themselves. Five French TV crew members and two Argentinian pilots also lost their lives.

French President Francoise Hollande released a statement on Twitter saying simply “The sudden death of our fellow French nationals is a cause of immense sadness,” the BBC has reported.

The three athletes were named as Camille Muffat, 25, an Olympic swimmer who won three medals including Gold in the 400m freestyle in the 2012 London Olympics; Alexis Vastine, 28, an Olympic boxer who won bronze in the light-welterweight category at the 2008 Beijing Olympics; and Florence Arthaud, 57, a hugely accomplished sailor who in 1990 won the prestigious solo Atlantic race, the Route de Rhum.

The cause of the crash in La Rioja province, close to the Andes mountain range in north west Argentina, is as yet unknown. Weather conditions are said to have been good at the time of the crash, leading to speculation that the two helicopters flew into each other.

La Rioja Secretary of Security Cesar Angulo has said “An explosion occurred and it’s believed that they must have collided. Aeronautical experts will have to determine that.”

Tributes are pouring in on social media from across France, where the hashtag #Dropped has topped the trending lists on Twitter, as have the names of the three athletes. Former French footballer Sylvain Wiltord, who was a fellow contestant on the show, said he was “sad for my friends, trembling, horrified, lost for words.”

Tributes have also come from further afield, as athletes who competed against the trio also paid their respects. British Olympic swimmer Rebecca Adlington has tweeted “So sad and shocked to wake up to hear the tragic death of Camille Muffat. She was an amazing sportswoman, competitor and lovely person,” adding “You will be dearly missed”.

And British boxer Stephen “Swifty” Smith described Alexis Vastine as a “nice lad”

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Culture Minister Fleur Pellerin told news channel BFM-TV that the lost athletes were “among the most outstanding ambassadors for our country”.

The other victims of the crash were named as Laurent Sbasnik, Lucie Mei-Dalby, Volodia Guinard, Brice Guilbert and Edouard Gilles, all of whom worked for Adventure Line Productions (ALP), the company making the program for TV channel TF1. The Argentine pilots were named as Juan Carlos Castillo and Roberto Abate.

TF1 has issued a statement saying “We learn with great sadness about the accident during the filming of the Dropped show. All TF1 teams come together in this terrible time with the pain of the families and relatives of the victims.”

Filming of the show has been postponed and all other participants and crew members are now returning home. Philippe Candeloro, a figure skater who was also taking part in filming was said to be “extremely shocked but unharmed”.