An EgyptAir flight from Paris to Cairo has disappeared from radar, the Egyptian airline says.
It says there are 59 passengers and 10 crew members on board Flight MS804.
The aircraft was flying at 37,000ft (11,300m) when it went missing over the eastern Mediterranean. An official said the plane lost contact with radar at 02:45 Cairo time (00:45 GMT).
The company said it would issue an update “when more information becomes available”.
EgyptAir said the plane disappeared about 10 miles (16km) into Egyptian air space.
It said the concerned authorities had been notified, and search and rescue teams were now looking for the aircraft.
The search operation is being co-ordinated with the Greek authorities.
According to the flightradar24.com website, which tracks passenger flights around the globe, the plane is an Airbus A320.
The aircraft left Paris at 23:09 local time on Wednesday (21:09 GMT) and was scheduled to arrive in the Egyptian capital soon after 03:00 local time on Thursday.
In March, an EgyptAir plane was hijacked and diverted to Cyprus. The attacker later surrendered and all hostages were released.
Last October, a Russian passenger plane flying from Sharm el-Sheikh crashed over the Sinai peninsula killing all 224 people on board. Officials in Moscow later said the aircraft was brought down by an explosive device.
Islamic State militants said they had bombed the plane.