EgyptAir flight messages showed smoke on board
"There were ACAR messages emitted by the plane indicating that there was smoke in the cabin shortly before data transmission broke off," a spokesperson of France's Bureau of Investigations and Analysis told AFP.
ACAR, which stands for Aircraft Communications Addressing and Reporting System, is a digital system that transmits short messages between aircraft and ground stations.
The spokesperson said it was "far too soon to interpret and understand the cause of Thursday's accident as long as we have not found the wreckage or the flight data recorders”.
The Wall Street Journal, citing people familiar with the matter, earlier reported that automated warning messages indicated smoke in the nose of the aircraft and an apparent problem with the flight control system.
The warnings came about three minutes before air traffic controllers lost contact with the plane at 00:29 GMT on Thursday, the Journal said.
The messages indicated intense smoke in the front portion of the plane, specifically the lavatory and the equipment compartment beneath the cockpit. The error warnings also indicated that the flight control computer malfunctioned, the report said.
CNN also reported smoke alerts on the flight minutes before it crashed, citing an Egyptian source.
On Friday, search teams found wreckage including seats and luggage about 290km north of Egypt's coastal city of Alexandria, Egypt's military said.
The plane disappeared without any distress signal between the Greek island of Karpathos and the Egyptian coast.
It had turned sharply twice in Egyptian airspace before plunging 6 700m and vanishing from radar screens, Greek Defence Minister Panos Kammenos has said.