Greek state television said aircraft debris had been found in the sea during a search for the missing Airbus A320. Earlier, Greek officials said pieces of plastic and two lifevests were found floating some 230 miles south of Crete, according to Reuters.
According to Al Arabiya, two bodies were also found in the search area.
Officials were reluctant to speculate over the disappearance while the search was underway. Egyptian Prime Minister Sherif Ismail said it was too early to rule out any explanation, including an attack like the one blamed for bringing down a Russian airliner over Egypt's Sinai peninsula last year.
But despite the caution, the country's aviation minister said a terrorist attack was more likely to have taken down the aircraft than a technical failure.
In Washington, U.S. President Barack Obama received a briefing on the disappearance from his adviser for homeland security and counter-terrorism, the White House said.
Read alsoEgypt PM says cannot rule out terrorism behind vanished planeIn Athens, Greek Defence Minister Panos Kammenos said the Airbus had first swerved 90 degrees to the left, then spun through 360 degrees to the right. After plunging from 37,000 feet to 15,000, it vanished from Greek radar screens.
Greece deployed aircraft and a frigate to the area to help with the search. Greek defense sources told Reuters earlier that two floating objects, colored white and red, had been spotted in a sea area 230 miles south of the island of Crete.
According to Greece's civil aviation chief, calls from Greek air traffic controllers to the jet went unanswered just before it left the country's airspace, and it disappeared from radar screens soon afterwards.