Even so, a French military spokesman, Col. Gilles Jaron, said in Paris late Thursday that he could not confirm that any wreckage had been located. Fifty-one of the passengers on the plane were French citizens, and when it was reported missing Thursday morning, French warplanes based in the region were dispatched to hunt for it. “We are continuing the search,” Colonel Jaron said.

President François Hollande canceled a trip to the island of Comoros and the French territories of Reunion and Mayotte and called his cabinet together in Paris for an emergency meeting Thursday afternoon. “We still don’t know what happened,” Mr. Hollande said in the evening after the meeting. “What we know is that the crew signaled at 1:48 a.m. that it was changing direction because of a particularly difficult weather situation.”

France, which once ruled the region as a colonial power, retains extensive political and economic interests and a significant military presence in West Africa. It led an international effort last year to expel Islamist militants from towns in northern Mali that were overrun by Al Qaeda’s North African affiliate in 2012. The militants left behind stacks of manuals explaining in detail how to use SA-7a and SA-7b shoulder-fired antiaircraft missiles, which can shoot down an airliner flying low for takeoff or landing. But those militants are not known to possess heavier weapons that could strike an aircraft at cruising altitude.

Flight 5017’s usual northward route to Algiers would have taken it over desert areas where the militant groups have been active. But French military officials in the region said it was highly unlikely that the Air Algérie flight had been shot down, the way Malaysia Airlines Flight 17 was in eastern Ukraine a week ago.

Instead, early guesses about the cause of the crash have focused on the weather.

The Burkina Faso government said that the aircraft’s last contact with ground control came a few minutes after it had passed northward out of the country’s air space. It said the crew contacted air traffic controllers in Niamey, Niger, at 1:47 a.m. local time, and informed them that the plane had encountered storms.

Residents of northern Mali reported a heavy sandstorm overnight. “There was a lot of damage from the wind, especially in the region of Kidal,” said Kata Data Alhousseini Maiga, an official with the United Nations mission in Gao, Mali. “The sand was so thick that you couldn’t see.”