A plane travelling from Paris to Cairo has disappeared from radar, airline EgyptAir said.
EgyptAir flight MS804 left Charles De Gaulle Airport at 11.09pm Central European Summer Time, according to the airline.
The airline said there were 59 passengers on board.
The airline's official Twitter account posted a message saying: "An informed source at EGYPTAIR stated that Flight no MS804,which departed Paris at 23:09 (CEST), heading to Cairo has disappeared from radar."
A previous tweet in Arabic said that the plane had disappeared in the early hours of the morning after leaving.
The airline tweeted in Arabic that the plane lost contact with radar at 2.45am Cairo time. Cairo International Airport's website listed the flight's scheduled arrival time as 3.05am.
In another tweet in Arabic, EgyptAir said the plane disappeared from radar 10 miles after entering Egyptian airspace.
The Airbus A320 had 10 crew members on board and was flying at 37,000 feet.
The airline tweeted: "EGYPTAIR has contacted the concerned authorities and bodies and inspection is underway through the rescue teams."
In March, a domestic EgyptAir flight with 72 passengers on board had to make an emergency diversion to Larnaca, Cyprus, after an alleged hijacking.
In October 2015, 224 people were killed when a Russian aircraft crashed over Egypt's Sinai Peninsula minutes after it took off from the Red Sea resort of Sharm el-Sheikh.