There are Indications that the missing EgyptAir flight sent a distress message before vanishing from radar on Thursday morning.
The airline said the message was detected by the military.
The message was received at 0226 GMT, less than 10 minutes before the flight disappeared, an EgyptAir official told AFP.
The EgyptAir plane headed to Cairo from Paris with 69 people on board disappeared from radar at dawn Thursday.
Flight MS804 operating an Airbus A320 took off from Charles de Gaulle airport at 11:09 p.m. with 59 passengers and 10 crew members, the carrier said in a statement. The aircraft lost communications with radar around 2:45 a.m. Cairo time, it said in a separate statement.