Egypt Air Flight MS804 that went off radar screens early on Thursday while en route from Paris to Cairo went down into the Mediterranean Sea, the Al Mayadeen TV channel reports citing airline sources.
Flight MS804, en route from Paris to Cairo, went off radar screens at 00:45 GMT on Thursday, according to Egypt Air.
Egypt Air said via Twitter that the plane was 10 miles into the Egyptian airspace and at an altitude of 37,000 feet when radar contact with it was lost.
According to Sky News Arabia, the aircraft's last appearance was above Greece.
"Special teams arrived to search and rescue of the Egyptian armed forces to specified location to search and still searching," Egypt Air said in a Tweet.
According to the airline, there were a total of 66 people on board the plane, including 56 passengers. Earlier reports said that there were 59 passengers and 10 crew on board.
"Egypt Air is following the situation closely with the competent authorities through the integrated operations centre," Egypt Air said via Twitter.
Egypt Air Flight MS804 departed from the Charles de Gaulle Airport in Paris at 23:09 GMT. The plane was headed for Cairo International Airport.
According to Egypt Air, the making year of the Airbus A320 aircraft is 2003.
Egyptian aviation authorities are cooperating with the Greek authorities over the plane's disappearance.