An EgyptAir flight carrying 56 passengers and 10 crew members on a flight from Paris to Cairo disappeared from radar over the Mediterranean minutes before it was expected to land.
A search is underway but officials said they believed the jet went down in the sea.
The French President said authorities have been “mobilised” and inquiries have started.
“The truth will be found,” he said, expressing his condelences to everyone involved. “No hypothesis is discounted, no hypothesis is privileged.”
Sky news reports:
French President Francois Hollande said “unfortunately the information we have … confirms to us the plane came down and is lost”, suggesting it crashed near the southern Greek island of Karpathos where the search is focused.
At the same time, Greek defence minister Panos Kammenos said the aircraft was in Egyptian airspace and flying at 37,000ft when it made “sudden swerves” and plunged to 15,000ft.
He said it swerved “90 degrees left and then 360 degrees to the right” before vanishing.
Flight MS804 departed the French capital at 11.09pm (CEST). The airline said the plane lost contact with radar at 2.45am Cairo time (1.45am BST). It was last in touch 10 minutes earlier.
At that stage the Airbus A320, which was 13 years old and had logged 48,000 flight hours, was about three hours and 40 minutes into the four-hour journey.