UPDATE: Greek sources have reportedly confirmed MS804 crashed off the Greek Island of Karapathos in Egyptian Airspace. 

Earlier unconfirmed footage emerged of a fireball descending towards the sea off the island. 

WHAT WE KNOW:

• EgyptAir flight MS804 has disappeared with 66 souls on board, including two babies and one child
• It left Paris at 11.09pm local time (7.09am AEST)
• A distress signal was reportedly sent from the plane about 4.26am (local time).
• At the time it was at 37,000 feet and inside Egyptian airspace.
• The missing plane is an Airbus A320.
• Flight radar websites suggest contact was lost over the Mediterranean Sea.
• No Australians were on board the flight.

LOCALS on a Greek Island as well as sailors from the merchant navy have reportedly told Greek investigators they saw a fireball in the sky around the time missing EgyptAir MS 804 flight fell off the radar.

Earlier this evening EyptAir released the nationalities of the passengers on board flight.

The airline says 15 French people, 30 Egyptians, one Brit, one Belgian, two Iraqis, a Kuwaiti, a Saudi, a Canadian, a Sudanese citizen, a Chadian, one person from Portugal, and an Algerian, made up the nationalities of those on board the flight.  

The airline has tweeted that the plane was carrying 66 people including one child, two infants, three EgyptAir security personnel, seven cabin crew and 53 adult passengers.

It has also said the plane sent a distress signal that was received at 4.26am (local time).

Egyptian armed forces special teams are presently searching the area where it's believed the plane went down. 

EgyptAir took to Twitter saying its flight commander has  6275 hours  flying hours experience including 2101 hours on the same model (Plane made in 2003) and the Copilot has 2766 hours.

EgyptAir flight MS804 took off from Paris Charles de Gaulle Airport bound for Cairo at 11.09pm Paris time (7.09am AEST).

It was due to arrive at Cairo Airport at 3.15am local time. It disappeared about 30 minutes before that at 2.45am (10.45am AEST)

It's believed the plane was about 10km inside Egyptian airspace. 

The plane is understood to be an Airbus A320. Weather in the area where the plane was lost is reported to have been clear.

The disappearance marks the second significant incident to affect the airline in the past six months.

In March, flight MS181 was taken over by a passenger who claimed to be wearing a suicide explosive belt.

MS181 was travelling to Cyprus.

The hijacker's explosive belt was later discovered to be false.