At least 13 French soldiers have died after two military helicopters collided in Mali.
The accident happened on Monday during a combat operation against jihadist insurgents in the African country.
Six soldiers and six officers were amongst the fatalities, officials confirmed.
"The president announces with deep sadness the death of 13 French troops in Mali on the evening of Nov. 25, in an accident between their two helicopters during a combat mission against jihadists", an official Elysée statement said.
French president Emmanuel Macron expressed "deep sadness" and hailed the sacrifice of the men "who died in the difficult fight against terrorism in the Sahel".
It continued: "He bows to the grief of their families and their loved ones and sends them his most sincere condolences, assuring them of the unfailing solidarity of the Nation."
The accident involved a Tiger attack helicopter, and an Airbus Helicopters Cougar, a twin-engined aircraft used by the French Army in assaults.
The incident is the single biggest loss of French troops in the region since intervening there in 2013.
Ed Llewellyn, Britain’s Ambassador in Paris Tweeted: ‘All our condolences to the families and relatives of the 13 French soldiers who died #Mal
France has more than 4,500 troops countering Islamist insurgencies in the Sahel region which is under threat from militants linked to al Qaeda and Islamic State.
The militants use central and northern Mali as a launch pad for attacks across the largely desert region.
Ms Parly said: ‘In this war nothing is obvious, it’s an asymmetric war.
"It’s a war that combines the struggle against terrorism with local situations of ancestral conflicts or tensions between communities."
Monday's deaths brings the total number of French soldiers killed in the Sahel to 28.
