Aviation experts, criminal investigators and soldiers have converged on an isolated patch of northern Mali to search for clues that might explain why an Air Algerie passenger jet fell from the sky in a storm and apparently disintegrated on impact.
French authorities said on Friday that the air disaster was probably the result of extreme bad weather, but they refused to exclude other possibilities without a full investigation.
All 118 people on board the plane, nearly half of them French, were killed. The passenger list also included other Europeans, Canadians and Africans. The six crew members were Spanish.
Investigators at the scene concluded the McDonnell Douglas MD-83 aircraft broke apart when it smashed into the ground early on Thursday, officials said, suggesting this meant it was unlikely to have been the victim of an attack.
"French soldiers who are on the ground have started the first investigations," French President Francois Hollande said. "Sadly, there are no survivors."
The plane was flying from Ouagadougou, capital of Burkina Faso, to Algiers, Algeria, when it disappeared just 50 minutes after take-off.
One of plane's two "black boxes" - flight data and cockpit voice recorders- was found on Friday and sent to Gao, the northern Malian city where a contingent of French troops is based.
Video of the wreckage site taken by a soldier from Burkina Faso, the nation first on the scene, showed debris scattered over a desolate area dotted with scrubby vegetation.
There were bits of twisted metal but no identifiable parts such as the fuselage or tail, or victims' bodies.
Difficult access to the area and instability could hinder the investigation. Gao is in the heart of a still-turbulent desert and mountain area that fell under the control of rebels after a 2012 military coup.
French forces intervened in the West African country in January 2013 to battle al-Qaeda-linked fighters controlling the region.
The debris field to the south is in a concentrated area in the Gossi region near the border with Burkina Faso. The area is "in a zone of savannah and sand with very difficult access, especially in this rainy season," Laurent Fabius, French foreign minister, said.
It's too early to know "with absolute certitude" what caused the disaster, he said, but he noted major storms in the region.
The pilot of the jet had advised controllers in Niger that he needed to change routes because of a storm, Jean Bertin Ouedraogo, Burkina Faso transport minister, said on Thursday. Contact with the plane was then lost.
The Air Algerie crash was the third worldwide in the space of just eight days.
On July 17, a Malaysia Airlines plane was shot down in eastern Ukraine, killing all 298 people on board.
A Taiwanese aircraft crashed in torrential rain in Taiwan on Wednesday, killing 48.