Two Olympic athletes who won medals for France were among ten people killed Monday when two helicopters crashed in a remote area of northwest Argentina.

Eight of the victims were French citizens, including swimmer Camille Muffat and boxer Alexis Vastine. The athletes were part of a crew filming the reality show "Dropped," a survivalist program that is broadcast throughout Europe.

Muffat, 25, won three medals at the 2012 Olympic Games in London, including gold in the 400-meter freestyle. Vastine, 28, won a bronze medal in the light welterweight division at the 2008 Olympics in Beijing.

Florence Arthaud, 57, a champion sailor, also was among the dead in the crash. In 1990, she won the famed Route du Rhum race — a trans-Atlantic single-handed yacht race between Brittany and the Caribbean islands of Guadeloupe — on her boat Pierre 1er.

"The brutal demise of our compatriots is an immense sadness," said French President Francois Hollande in a statement published on the website of the French daily Liberation.

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"Some had finished their careers and one was dreaming of gold in Rio," French Secretary of State for Sport Thierry Braillard said Tuesday on BFM TV channel. "I'm profoundly saddened. French sport has lost three stars this morning."

Hollande's statement identified the remaining victims as Laurent Sbasnik, Lucie Mei-Dalby, Volodia Guinard, Brice Guilbert and Edouard Gilles, as well as Argentine pilots Juan Carlos Castillo and Roberto Abate.

Sylvain Wiltord, a former soccer star who played for the French national team as well as the English club Arsenal and reportedly one of the show's contestants, tweeted: "I'm sad for my friends, I'm trembling, I'm horrified, I have no words, I don't want to say anything."

The helicopters crashed near the town of Villa Castelli in La Rioja province, about 730 miles northwest of Buenos Aires, La Rioja Secretary of Security Cesar Angulo told television station TN.

"An explosion occurred and it's believed that they must have collided," said Angulo. "Aeronautical experts will have to determine that."

The TV show's crew had arrived on Sunday in Villa Castelli, where it had previously filmed a version of the show for Switzerland and Denmark, said Villa Castelli mayor Andres Navarrette.

"The causes of the crash are not known," Navarrete told radio station Cadena 3.

Photographs showed the burning and smoking wreckage of the helicopters on the ground with people gathered nearby.

Angulo said one of the helicopters belonged to La Rioja province and the other belonged to the neighboring province of Santiago del Estero.

The rugged, sparsely populated area is on the edge of the Andes mountain range that separates Argentina and Chile. The crash happened at around 5:15 p.m. local time, according to Argentine news agency Telam, which also reported that parts of the wreckage were still on fire hours after the crash.

Several after-hours calls to various departments within the municipality of Villi Castelli were not answered.

The deaths are likely to place new attention on the risks involved with reality TV shows, which have been highly popular and sometimes involve taking celebrities and others to far-flung locations to face challenges against the natural elements — both physical and mental.

Two years ago, TF1 — France's best-known private-sector network, which aired the show — canceled the remaining season of the "Survivor"-like reality show "Koh Lanta" after a 25-year-old participant died of a heart attack on the first day of filming.

French Prime Minister Manuel Valls said France's foreign ministry is in contact with authorities in Argentina to determine what caused the crash.

Adventure Line Productions, the show's producers, said in a statement that its teams were "devastated and share the deep pain of the families and loved ones."

"We are in contact with the production teams on site (and) with the French and Argentine authorities. We will give more information as soon as possible," the producers added.

International Olympic Committee President Thomas Bach said the Olympic flag will be flown at half-staff for three days IOC headquarters.

He added that the athletes "were all not only champions in their sport, but also contributed greatly as role models."

The Associated Press contributed to this report.