France has lost a "brave friend," the French presidency has said following the battlefield death of Chad's president Idriss Deby.
He was killed on the frontline in Chad's north where soldiers have been fighting rebels, the military announced on Tuesday (April 20).
His death could potentially deepen Chad's problems, and those of its allies.
France and the United States viewed Deby as an important ally in the fight against militants in the Sahel region.
Former colonial power France has based its Sahel counter-terrorism operations in the capital N'Djamena.
In February Chad announced the deployment of 1,200 troops to complement 5,100 French soldiers in the area.
A statement from the office of French President Emmanuel Macron said Chad had lost "a great soldier."
Deby often joined soldiers on the battlefront, dressed in his military fatigues.
On Monday (April 19), the day he was announced as winner of a presidential election, he had joined troops fighting rebels who had advanced from Chad's northern border with Libya.
Following his death, an army spokesman said Deby's son, Mahamat Kaka, had been named interim president by a transitional council of military officers.
The government and National Assembly were also dissolved and a nationwide curfew imposed.
The French presidency's statement noted the formation of the interim council but said it hoped there would be a quick and peaceful return to civilian rule.
Deby's death, following more than three decades of rule, could also spell uncertainty for Chad.
It's military is divided and the opposition is restless following years of repressive rule.
Public discontent had already been mounting over Deby's crackdowns on opponents and mismanagement of Chad's oil wealth.
A Reuters reporter in N'Djamena said people were in a panic as news of his death spread, fearing that fighting could break out in the city.
Many were fleeing to the outskirts and roads were jammed with traffic.