An EgyptAir airliner which went missing on Thursday morning made 'sudden swerves' in mid-air and plunged before dropping off radars in the southern Mediterranean, Greek defence minister Panos Kammenos said.

The EgyptAir flight with 66 people on board dropped off radars over the Mediterranean sea about 280 miles off the coast of Egypt. It had been flying from Paris to Cairo.

Greek authorities have mounted a search in the area south of the island of Karpathos without result so far, Kammenos said.

"At 3.39am (0039 GMT) the course of the aircraft was south and south-east of Kassos and Karpathos (islands)," he told a news conference. "Immediately after, it entered Cairo FIR (flight information region) and made swerves and a descent I describe; 90 degrees left and then 360 degrees to the right."

The Airbus plunged from 37,000 feet to 15,000 feet before vanishing from radar, he added.

Officials with the airline and the Egyptian civil aviation department told Reuters earlier they believed the jet had crashed into the Mediterranean between Greece and Egypt. – Reuters