Egyptian authorities reported a distress signal had been issued "in the vicinity" of where the missing flight disappeared while travelling from Paris to Cairo above the Mediterranean Sea on Thursday.

The New York Times reported two security officials at Cairo International Airport saying the plane was presumed to have crashed, however the airline is still referring to the plane's plight as a "disappearance". Egyptian authorities have yet to offer a theory for why the plane disappeared from radar.

A relative of the victims of the EgyptAir flight 804 wipes her tears as she is comforted at Charles de Gaulle Airport outside of Paris. Photo: AP

Authorities from Egypt and Greece have launched a search with planes and boats in the area the plane was last detected.

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The Greek defence ministry said it was investigating an account from the captain of a merchant ship that he saw a 'flame in the sky' around 240 kilometres south of the Greek island of Karpathos.

In a statement, Egypt's civil aviation ministry said it was too early to confirm the plane had crashed.

A child and two babies are among the 66 people on board the Airbus A320, which disappeared from radar shortly after entering Egyptian airspace, EgyptAir said on Thursday.

Flight MS804 took off from Charles de Gaulle Airport in Paris at 11.09pm on Wednesday local time (7.09am AEDT), and was scheduled to land in Cairo at 3.15am on Thursday.

Ahmed Adel, the vice-chairman of EgyptAir, confirmed that 56 passengers and 10 crew members were on board at the time the plane disappeared.

EgyptAir flight MS804 was travelling between Paris and Cairo when it vanished from radar. Photo: flightradar24

The passengers, including 53 adults, two infants and one child, are from 12 countries. Most of the passengers are from Egypt, with 30 citizens on board, while 15 are from France.

Two of the passengers are from Iraq, and one passenger each from Britain, Canada, Belgium, Kuwait, Saudi Arabia, Sudan, Chad, Portugal and Algeria.

A total crew of 10 is on board, including two cockpit crew, five cabin crew and three security staff.

The EgyptAir aircraft that was hijacked during a flight from Alexandria to Cairo in March. Photo: AP

EgyptAir said the plane's last known position was above the Mediterranean Sea about 280 kilometres from the Egyptian coast.

Search and rescue teams from Egypt and Greece have launched a search on the water and in the air for the plane, which authorities from Egypt's Civil Aviation Ministry believe has most likely crashed into the water.

Technical information on the condition of the plane was being gathered.

Relatives and families of those on board have been taken to a holding room by EgyptAir for further updates. The airline said on Twitter that concerned relatives from outside Egypt could phone +202 259 89320 for more information.

The plane's captain and first officer each had several thousand hours of flying experience, including on the type of plane they were flying on Thursday.

EgyptAir said the flight was cruising at 37,000 feet when it disappeared from radar at 2.30am Cairo time, 45 minutes before it was due to land. 

Authorities received a "distress message" from "the vicinity" where the plane was last seen, EgyptAir said, adding it hoped media would report official statements released by the airline.

The distress signal detected by armed forces almost 2 hours after the plane disappeared from radar.

EgyptAir were not able to confirm if the signal came from the plane or a nearby boat.

Initially, it was believed the plane "just vanished" and did not radio for help or lose altitude. The weather at the point where the plane disappeared from radar was reported to be clear.

CNN reporter Ian Lee said "distraught" relatives were continually arriving at Cairo International Airport but none had spoken so far.

France's foreign minister Jean-Marc Ayrault confirmed 15 French citizens were on board the plane and said France will send planes and boats to assist in the search.

It is not believed any Australians were on the flight.

The Paris airport authority and the French civil aviation authority would not immediately comment.

Egypt's tourism hard hit

With its ancient archeological 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 hijacking of an EgyptAir jet in March, the ongoing Islamist insurgency and a string of bomb attacks in the country.

In an unrelated incident in March, an EgyptAir plane was hijacked during a flight from Alexandria to Cairo.

Egyptian Seif Eldin Mustafa, wearing what appeared to be a suicide belt, took over the aircraft and forced the pilots to fly to Cyprus, where he hoped to be reunited with his estranged wife.

After a six-hour hostage drama, the hijacker was arrested after giving himself up. The "bomb" was later found to be fake, and no one was injured.

An Airbus A321 operated by Russia's Metrojet crashed in the Sinai in October 2015, killing all 224 people on board. Russia and Western governments have said the plane was most likely brought down by a bomb, and the Islamic State militant group said it had smuggled an explosive on board.

An EgyptAir mechanic, whose cousin joined Islamic State in Syria, is suspected of planting the bomb.

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 100 kilometres south of Nantucket Island, Massachusetts, killing all 217 people on board.

With Reuters, AP, AAP, New York Times

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