"A witness informed us they had seen the plane falling at 0150 (GMT and local time Thursday)," said General Gilbert Diendiere, coordinator of the crisis unit established in Ouagadougou to try and find the jet.
"We are in contact with the witness and we intend to survey the site" to verify the information, he added.
"We believe this information is accurate as we have compared it to radar images showing the flight path until the plane disappeared," Diendiere said.
Air Algerie today said that it lost contact with the aircraft flying from Ouagadougou to Algiers 50 minutes after it took off from the Burkina Faso capital.
An airline source in Algiers told AFP that the plane was over northern Mali when contact was lost.