Ten people, including Olympic gold medalist swimmer Camille Muffat and two other French sports stars, were killed Monday in a horrific helicopter crash while they were filming a reality TV show, the Agence France-Presse reports.

The athletes were filming a segment for the survival show Dropped, in which eight sports stars are left in a remote location and tasked with finding their way back to civilization, in Argentina when their helicopters collided in mid-air. There were no survivors.

See other celebrities we've lost in 2015

The cause of the crash is under investigation and production on the show has stopped.

In addition to Muffat, Olympic boxer Alexis Vastine and sailing champion Florence Arthaud, as well as the two Argentine helicopter pilots and five members of the reality show's crew, were among the casualties.

"The whole of France is in mourning this morning," Prime Minister Manuel Valls said, as reported by the AFP.

Muffat, 25, won a gold, silver and bronze at the London Olympics in 2012 and retired last year. Vastine, 28, won a bronze medal at the 2008 games in Beijing. Arthaud, 57, is best known for winning the Route du Rhum in 1990.