Russian spy chief: 'Terrorist attack' downed EgyptAir plane

​EgyptAir MS804 was the target of a "terrorist attack", Russia's chief spymaster said on Thursday.

The flight, which went missing en route between Paris and Cairo, was brought down by an armed group's plot, said Alexander Bortinov, the president of the Russian Federal Security Service.

"Unfortunately has been another incident today concerning an Egyptian Airlines Plane. It appears this is a terrorist action that has killed 66 citizens of about 12 countries," Bortnikov told Russian media outlets.

The security official called on all parties concerned including partners in Europe to cooperate to "identify people who are involved in this terrible work".

Egypt's prosecutor-general has ordered a state security investigation into the missing plane.

During a press conference on Thursday, the Egyptian National Security Council said that the government must provide "all aspects of assistance" to the families of the passengers and crew-members.

	Video: The plane disappeared around 175km from Egypt's coast

The council, chaired by Egyptian President Abdel Fattah el-Sisi, presented Minister of Civil Aviation Sherif Fathi with the information available thus far.

"When I have facts I will tell you the facts," Fathi told the conference. "What else can I do?"

The council said it would continue efforts to search for the aircraft with Egyptian naval vessels and work with the cooperation of France and Greece to uncover the circumstances which led to the disappearance of the plane.

French President Francois Hollande confirmed EgyptAir flight crashed, refusing to rule out any hypothesis, saying marine rescue workers would spare no effort to find the missing.

Paris' prosecutor's office has also announced an investigation into the EgyptAir crash.

Greek Defence Minister Panos Caminos, meanwhile, said the Egyptian plane veered suddenly at an altitude of 37,000ft - within Egyptian airspace - before dropping suddenly and losing contact at 22,000 feet.

"That's all we have so far," Caminos said.

Greek media has reported that the search-and-rescue process has spotted aircraft debris off the Greek island of Karpathos, but such reports have yet to be confirmed by officials.