EgyptAir flight 804 goes missing over the Mediterranean. Terrorist attack?

A plane carrying 66 people from Paris to Cairo disappeared from radar early Thursday morning, prompting an international search as some aviation experts suggested that an act of terrorism could have brought down the aircraft. 

EgyptAir Flight 804 had departed Charles de Gaulle Airport outside of Paris at 11:09 local time Wednesday evening and was scheduled to land at 3:15 Thursday morning in Cairo.

At 3:27 a.m., controllers repeatedly attempting to communicate with the pilots received no response as the aircraft neared the edge of Greek airspace. Within minutes they had entered Egyptian airspace, and 40 seconds later radar contact was lost.

Greek Defense Minister Panos Kammenos told reporters that the plane "swerved and then plunged" over the Mediterranean Sea. He said the aircraft made a 90-degree left turn, then a full 360-degree turn toward the right, dropping from an altitude of 38,000 to 15,000 feet. It dropped from sight at about 10,000 feet, the Associated Press reported.

Egyptian and Greek vessels and aircraft are currently searching for wreckage or survivors. The US Navy has also deployed aircraft from Sicily to support the search, according to The Guardian. 

Two orange items believed to possibly be from the flight were recovered in Egyptian air space, 230 miles south of Crete, according to Greek military officials.  

Meanwhile, relatives gathered at both Paris and Cairo airports, where they were provided with translators and psychiatric specialists as they waited for further information.

Those on board, according to EgyptAir, included 15 French passengers, 30 Egyptians, two Iraqis, one Briton, one Kuwaiti, one Saudi, one Sudanese, one Chadian, one Portuguese, one Belgian, one Algerian and one Canadian.

Egyptian security officials said they were running background checks on the passengers to see if any had links to extremists, the Associated Press reported.

The disappearance has not been attributed to any specific cause. French President François Hollande told reporters in Paris, however, that information "unfortunately confirm[s] to us that this plane crashed at sea and has been lost," according to The New York Times.

Mr. Hollande added that "no hypothesis was being ruled out and none is being favored."

Yet others, such as the chief of Russia's Federal Security Service, Alexander Bortnikov, have claimed the disappearance was a terrorist attack, a hypothesis on many analysts' minds after the past year's attacks in Paris and the downing of Russian Metrojet Flight 9268 over Egyptian airspace, all of which were claimed by the Islamic State terrorist group. 

While no current mention of the disappearance of flight 804 has been made on ISIS-affiliated websites, Egyptian officials now believe that terrorism is the most likely cause, The Guardian reported.

"If you [analyze] the situation properly, the possibility of having a terror attack is higher than the possibility of having a technical fault," Egypt's aviation minister, Sherif Fathy, told reporters. Mr. Fathy cautioned, however, that no definitive conclusions could be made until wreckage and the airplane's blackbox, the device recording cockpit activity, were recovered. 

Based on circumstantial evidence, US officials are also operating on the early theory that a bomb explosion caused the crash, according to CNN. 

"Planes just do not fall out of the sky for no reason, particularly [while cruising] at 37,000 feet," according to the station's aviation correspondent, Richard Quest.

In March an EgyptAir flight was hijacked and forced to land in Cyprus. However, all of the hostages were released, and the hijacker surrendered to Cypriot authorities, who later described the suspect as a mentally unstable man who had hoped to reunite with his Cypriot ex-wife.