EgyptAir flight that went missing between Paris and Cairo has crashed, according to French President Francois Hollande.
A major search and rescue operation is under way, involving the Greek and Egyptian armed forces. France has offered to send boats and planes to help.
National carrier EgyptAir said a plane carrying 66 passengers and crew on a flight from Paris to Cairo disappeared from radar over the Mediterranean at 00.30 GMT.
"An official source at EgyptAir stated that Flight MS804, which departed Paris at 23:09 (CEST), heading to Cairo has disappeared from radar," the airline said on its official Twitter account.
Later Tweets by EgyptAir said the plane, which was travelling at an altitude of 37,000 feet (11,280 metres), disappeared at 02:45 am, 20 minutes before it was due to land at 03:05 am, after entering Egyptian airspace.
The Airbus A320 aircraft was carrying 56 passengers, including one child and two infants, and 10 crew, EgyptAir said.
Earlier it said 59 passengers were aboard but then revised the figure.
The pilot had clocked up 6,275 hours of flying experience, including 2,101 hours on the A320, while the first officer had 2,766 hours, the airline said.
According to flightradar24.com, the 12-year-old plane's last known position was above the Mediterranean Sea.
Egypt's civil aviation ministry said search and rescue teams were looking for the missing jet. A ministry source also said technical information about the condition of the plane was being gathered.
The New York Times quoted Ehab Mohy el-Deen, the head of Egypt's air navigation authority, as saying that Greek air traffic controllers notified their Egyptian counterparts that they had lost contact with the plane. "They did not radio for help or lose altitude. They just vanished," he said.
Tourism disrupted
A spokesman at the French foreign ministry said checks were being carried out but the ministry had no further information. The French aviation authority could not be reached immediately for comment.
With its ancient archaeological sites and Red Sea resorts, Egypt is a popular destination for Western tourists. But the industry was badly hit following the downing of a Russian jet last year, the ongoing Islamist insurgency and a string of bomb attacks in the country.
An Airbus A321 operated by Russia's Metrojet crashed in the Sinai on October 31, 2015, killing all 224 people on board. Russia and Western governments have said the plane was likely brought down by a bomb, and the Islamic State militant group said it had smuggled an explosive device on board.
Reuters reported in January that an EgyptAir mechanic, whose cousin joined Islamic State in Syria, is suspected of planting the bomb, according to sources familiar with the matter.
In March, an EgyptAir plane flying from Alexandria to Cairo was hijacked and forced to land in Cyprus by a man with what authorities said was a fake suicide belt. He was arrested after giving himself up.
EgyptAir has a fleet of 57 Airbus and Boeing jets, including 15 of the Airbus A320 family of aircraft, according to airfleets.com.
The last fatal incident involving an EgyptAir aircraft was in May 2002, when a Boeing 737 crashed into a hill while on approach to Tunis–Carthage International Airport, killing 14 people.
In October 1999, the first officer of a Boeing 767 deliberately crashed the plane into the Atlantic Ocean about 60 miles south of Nantucket Island, Massachusetts, killing all 217 people on board.
