An EgyptAir flight heading from Paris to Cairo with 66 people board has crashed into the Mediterranean Sea and signs of possible wreckage have been found near a Greek island, amid suspicions of a possible terror attack.

“There have been finds southeast of Crete, inside the Cairo flight information area,” Greek military spokesman Vassilis Beletsiotis told AFP. He added that an Egyptian C-130 plane had spotted the floating objects, and ships would be sent to investigate. The Egyptian civil aviation agency had earlier confirmed that the plane had crashed after being reported missing.

US government officials are operating on an initial theory that the plane was brought down by a bomb, two US officials told CNN. However, they added that theory could change, with one senior administration official cautioning it is not yet supported by a "smoking gun."

Egypt's civil aviation minister has said the possibility of a terror attack is "stronger" than technical failure, while French Prime Minister Manuel Valls said no theory can be ruled out regarding the flight's disappearance.

The aircraft made two sharp turns before plunging into the Mediterranean Sea, said Greece's defence minister. Panos Kammenos said the Airbus A320 had "turned 90 degrees left and then a 360-degree turn to the right", before dropping more than 25,000-ft (7,620m) before disappearing from radar.

Flight MS 804, an Airbus A320, was flying at a height of 37,000 ft and was 10 miles (approximately 16 km) into the Egyptian airspace when it disappeared, the airline said. "EgyptAir has contacted the authorities concerned, and an inspection is underway through the rescue teams," the company tweeted.

The aircraft had 56 passengers and 10 crew members on board. According to EgyptAir, there were 30 Egyptians and 15 French nationals on board, among other nationals.

An official from the company told CNN that the plane was a relatively new Airbus 320.

The incident comes nearly two months after an EgyptAir flight travelling from Alexandria to Cairo was hijacked and flown to Cyprus. The hijacker was eventually arrested, and all passengers and crew members were released unharmed.