Three French sports personalities are among 10 people killed in a helicopter crash in Argentina, the French presidential office confirmed.

Eight French nationals and their two Argentine pilots died when two helicopters collided in La Rioja province in the country's north-west.

Yachtswoman Florence Arthaud, Olympic swimmer Camille Muffat and Olympic boxer Alexis Vastine all perished.

The helicopters were involved in the filming of TV survival show Dropped.

The show, on channel TF1, flies celebrities into rough terrain by helicopter and films their attempts to find food and shelter.

"The sudden death of our fellow French nationals is a cause of immense sadness," said a statement from French President Francois Hollande.

The cause of the crash is as yet unclear and investigations are under way.

Five of those killed were said to have worked for Adventure Line Productions (ALP), the company making the programme.

They were named as Laurent Sbasnik, Lucie Mei-Dalby, Volodia Guinard, Brice Guilbert and Edouard Gilles.

The Argentine pilots were named as Juan Carlos Castillo and Roberto Abate.

Filming had begun late last month at Ushuaia in the deep south of Argentina and had since moved to the mountainous western province of Rioja.

One cast member, figure skater Philippe Candeloro, was said to be "extremely shocked but unharmed".

Officials have said the weather conditions in the mountainous area where the helicopters went down were good.

"An explosion occurred and it's believed that they must have collided,'' said La Rioja Secretary of Security Cesar Angulo.

"Aeronautical experts will have to determine that," he added.

"We learn with great sadness about the accident during the filming of the Dropped show," said a statement issued by TF1.

"All TF1 teams come together in this terrible time with the pain of the families and relatives of the victims."

TF1 says the show will be postponed and the rest of the crew is returning home.

This is not the first time that a reality show produced for TF1 by ALP has been hit by tragedy.

Two years ago, a contestant died during the first day of production of one of the channel's ratings winners Koh-Lanta, an adventure show filmed in Cambodia.

Gerald Babin, 25, had suffered a cardiac arrest after taking part in a tug of war. He was treated by a staff doctor and was airlifted to hospital.

Barely a week later, the 38-year-old doctor, Thierry Costa, took his life complaining that his reputation had been sullied by media reports.

The 2013 season of the show was cancelled.

Source: BBC