EgyptAir flight 804 travelling from Paris to Cairo has disappeared from radar with 56 passengers and 10 crew members on board, the airline has said.
The Associated Press news agency quoted anonymous Egyptian aviation officials on Thursday as saying the plane crashed in the Mediterranean Sea.
The officials said the "possibility that the plane crashed has been confirmed," and the search is now underway for the debris, according to the news agency.
But, Egypt's civil aviation ministry later said in a statement that it was too early to confirm if the passenger plane has crashed.
According to EgyptAir, the plane took off from Paris' Charles De Gaulle Airport shortly after 11pm local time.
An informed source at EGYPTAIR stated that Flight no MS804,which departed Paris at 23:09 (CEST),heading to Cairo has disappeared from radar.— EGYPTAIR (@EGYPTAIR) 19. svibnja 2016.
"At 4:26am, rescue teams affiliated with the Egyptian armed forces have received an SOS message from the emergency unit of the missing plane," the airline said in a tweet. However, Egyptian army later denied detecting a distress signal from the missing plane, according to AFP news agency.
The Airbus A320 was flying at 37,000 feet when it disappeared 16km after entering Egyptian airspace, the airline said.
Egypt and Greece have launched maritime searches for missing flight, the Egyptian Army said.
EgyptAir has also published a list of passengers on board by nationality: 30 Egyptian nationals, 15 French, two Iraqis, one British, one Belgian, one Sudanese, one Chadian, one Portuguese, one Algerian, one Canadian, one Saudi and one Kuwaiti were on board, the airline said.
Three of those on board were children, including one infant, and three of the crew members were security personnel, EgyptAir reported.
'Sharing the anguish'
The French government held an emergency meeting at 06:30 GMT to discuss the plane’s disappearance, the French President Francois Hollande's office said.
"The President talked to Egyptian President Sisi about the disappearance of the EgyptAir flight between Paris and Cairo. They agreed to cooperate closely to establish the circumstances of the disappearance as soon as possible," a press release from the Elysee Palace stated.
"The President shares the anguish of the families affected by this tragedy."
French Prime Minister Manuel Valls said France is ready to join the search operation if Egyptian authorities request it.
Speaking on RTL radio, Valls said the Paris airport authority has opened a crisis center to support the families coming to Charles de Gaulle Airport.
Aviation experts said the plane probably lost contact with ground radar above the Mediterranean Sea.
"Apparently it was just short of Egyptian airspace, so it was likely over the Mediterranean, because the Greek airspace joins the Egyptian airspace around that area," aviation safety consultant Keith Mackey told Al Jazeera. "So that is probably where they will be looking."
"Egypt air should know exactly where the plane disappeared from radar," he said, "That would be the point where you begin your search. And it's very likely that that point is over the Mediterranean.
"As day light comes, no doubt they will have airplanes and ships searching the area. If it crashed, it should not take long to find it in that area. When a plane disappears suddenly like this you certainly cannot rule out terrorism or an explosion onboard the aircraft," Mackey said.
This is not the first air-safety crisis Egypt has faced recently.
In March, a domestic EgyptAir flight was hijacked and forced to land in Cyprus.
On October 31 last year, Russia-bound Metrojet Flight 9268, operated by Russian airline Kogalymavia, crashed in the Sinai Peninsula in Egypt , killing all 224 people on board.