Investigators have picked through the wreckage of two helicopters, removing mobile phones and other items, as France mourned the loss of prominent athletes in the crash in the Andean foothills.

The eight French nationals and two Argentine pilots on the two aircraft were killed when they collided and burst into flames shortly after taking off on Monday near the remote settlement of Villa Castelli in northwestern Argentina.

Among the victims were Olympic champion swimmer Camille Muffat, Olympic bronze-medallist boxer Alexis Vastine and pioneering sailor Florence Arthaud. They were contestants on the reality TV show Dropped, which was being shot in the sparsely populated region.

Sports stars pay tribute to athletes killed in helicopter collision

France seeks answers over sports stars killed in helicopter crash

Expressions of grief poured in from French athletes and officials, including from President Francois Holland, who said he felt “immense sadness”. The International Olympic Committee announced it would fly its flag at half-mast for three days.

French officials said they would work with Argentine investigators to determine the cause of the accident.

La Rioja’s aviation director, Daniel Gorkich, said that both pilots were highly trained and he speculated that afternoon sun and strong winds might have been a factor.

At the moment of impact “the sun was setting on the Andes mountain range directly in front of them. Also this is an area with wind gusts”, Mr Gorkich said.

A widely circulated video shows the blades of one helicopter hitting the rails of the second, causing both aircraft to lose control and crash.

Only blades left

Read the full story via Investigation into Argentina helicopter accident begins.