A black box recording from crashed EgyptAir flight MS804 confirms smoke on board, Egyptian investigators say.
The flight from Paris to Cairo plunged into the Mediterranean Sea on 19 May, killing all 66 people on board.
Automated electronic messages sent by the plane had shown that smoke detectors went off in a toilet and in the avionics area below the cockpit, minutes before the plane disappeared.
The recorded data are consistent with those messages, investigators said.
The voice and flight data recorders, known as black boxes, were recovered from a depth of about 3,000m (9,800ft) in the Mediterranean.
The second black box, the cockpit recorder, is still being repaired in Paris.
The Egyptian investigation committee also said that part of the front section of the aircraft's wreckage "showed sign of high temperature damage" and soot.
No distress call was made from the plane prior to the crash. The cause remains unknown, foreign media reports.