Among the dead were French Olympic gold medal swimmer Camille Muffat, Olympic boxer Alexis Vastine and sailor Florence Arthaud.

Two helicopters carrying French sports stars filming a popular European reality show crashed in a remote part of Argentina, killing 10 people, including two Olympic medal winners and a sailing champion, authorities said.

The helicopters apparently collided in midair yesterday near Villa Castelli in La Rioja province, about 730 miles (1,170 kilometres) northwest of Buenos Aires, La Rioja Secretary of Security Cesar Angulo told TN television. All 10 people on board, eight French nationals and two Argentine pilots, were killed.

“An explosion occurred and it’s believed that they collided,” said Angulo, referring to the helicopters.

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

Among the dead were French Olympic gold medal swimmer Camille Muffat, Olympic boxer Alexis Vastine and sailor Florence Arthaud, according to a statement from La Rioja’s government.

“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.

Muffat, 25, won gold in the 400—meter freestyle, silver in the 200—meter freestyle and a bronze in the 4x200—meter freestyle relay in the 2012 Summer Olympics in London.

Vastine, 28, won a bronze medal in the light welterweight division at the 2008 games in Beijing. Arthaud is considered one of the best sailors in the world.

The 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.

The athletes were part of a team filming the reality show .

“Dropped,” a survivalist program with several versions across Europe, said the mayor of Villa Castelli, Andres Navarrete.

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

Sylvain Wiltord, a former Arsenal footballer and reportedly one of the show’s contests who was not in either helicopter, tweeted: “I’m sad for my friends, I’m trembling, I’m horrified, I have no words, I don’t want to say anything.” Argentine authorities were at the scene of the crash late yesterday trying to determine its cause.

“The helicopter from La Rioja was a Eurocopter with a capacity to hold six people. It appears to have brushed against the other helicopter from Santiago del Estero shortly after takeoff,” the statement from the provincial government said.

A rugged, sparsely populated area is on the edge of the Andes mountain range that separates Argentina and Chile. The crash happened around 5:15 pm local time, according to Argentine news agency Telam. (