Monday's accident was the heaviest single loss for the French military in nearly four decades. All 13 aboard the two helicopters were killed.

The Islamic State's West Africa Province (ISWAP) said its fighters ambushed "a convoy of vehicles carrying Crusader French army elements near Indelimane village, in the Menaka area.

"As the Crusaders attempted to land from one of their helicopters, to descend on the position of the ambush, to support their soldiers, the soldiers of the Caliphate targeted it with medium weapons, forcing it to withdraw," the statement on the SITE intelligence group website said.

"After staggering in flight, it then collided with another helicopter, killing 13 Crusaders."

The accident brought to 41 the number of French troops killed in the Sahel region since Paris intervened against jihadists in northern Mali in 2013.

Since then, armed groups affiliated with the Islamic State group, Al-Qaeda and others have advanced into southern Mali as well as into neighbouring Burkina Faso and Niger.