[CAIRO] Egypt's president demanded authorities step up the search for an EgyptAir plane that crashed Thursday in the Mediterranean with 66 people aboard, after conflicting reports of wreckage being found.
His aviation minister said that while it was too soon to say why the Airbus A320 flying from Paris to Cairo had vanished, a "terrorist" attack would be a more likely scenario than a technical failure.
The tragedy raised fears of a repeat of the bombing of a Russian passenger jet by the Islamic State (IS) jihadist group over Egypt last October that killed all 224 people on board.
The plane vanished from radar screens between the Greek islands and the Egyptian coast overnight, without its crew sending a distress signal.
Greek Defence Minister Panos Kammenos said the aircraft had plunged 22,000 feet (6,700 metres) and swerved sharply twice in Egyptian airspace before it disappeared from radar screens.
Both Egypt and Greece dispatched aircraft and naval vessels on a search mission. They were expected to be joined by French teams, while the US send a surveillance plane to help with the operation.
Egypt's President Abdel Fattah al-Sisi demanded an "intensified search" for the aircraft after conflicting reports emerged about the discovery of debris.
The airline said on its Twitter account that the Egyptian civil aviation ministry had received "an official letter" from the foreign ministry "declaring the finding of wreckage of the missing aircraft No. MS 804 near Karpathos Island".
It also said floating "life jackets and plastic material" had been discovered.
But the head of the Greek air safety authority later told AFP that wreckage found close to the area where the EgyptAir went down "does not come from a plane".
French President Francois Hollande confirmed the plane had "crashed" as authorities in both Paris and Cairo opened investigations.
White House spokesman Josh Earnest said "it's too early to definitively say what may have caused this disaster".
Egypt's Aviation Minister Sherif Fathy said he was unable to "deny the hypothesis of a terrorist attack or something technical".
The airline said 15 French citizens were among the 26 foreign passengers on the plane, who also included a Briton and at least one Canadian.
Both France and Egypt have come under attack by IS jihadists in the past year, and Hollande promised a comprehensive probe into the cause of the crash as suspicions swiftly focused on a bomb.
"Whether it was an accident or another hypothesis that everyone has on their mind - a terrorist hypothesis... at this stage we must focus on our solidarity with the families and the search for the causes of the catastrophe," he said.
IS has been waging a deadly insurgency against Egyptian security forces and last October claimed the bombing of the Russian airliner flying home holidaymakers from the Egyptian resort of Sharm El-Sheikh.
EgyptAir said contact was lost with the flight about 280 kilometres (175 miles) north of the Egyptian coast.
A Greek aviation source said the flight had disappeared from Greek radar at around 0029 GMT.
"It crashed around 130 nautical miles off the island of Karpathos," the source told AFP, referring to an island northeast of Crete.
Greek civil aviation chief Constantinos Litzerakos said the pilot had mentioned no problem in the last communication before the plane disappeared, and it had not deviated from its course.
"The flight controllers contacted the pilot (with the plane) at a height of 37,000 feet (near Athens)... he did not mention a problem," Litzerakos told Greece's Antenna TV.
Neither the Greek coastguard nor the navy could confirm reports that a passing ship had seen "a ball of fire in the sky".
The civil aviation chief said if there had been an explosion, any debris would have scattered across a wide area.
EgyptAir Holding Company vice president Ahmed Adel also said there had been "no distress call" before the plane vanished.
The passengers also included two Iraqis and one citizen from each of Algeria, Belgium, Chad, Portugal, Saudi Arabia and Sudan, as well as 30 Egyptians, the airline said. They included a boy and two babies.
Seven crew members and three security men were also on board.
EgyptAir said the plane had been manufactured in 2003. Airbus said it had clocked up 48,000 flight hours.
EgyptAir hit the headlines in March when a flight from the coastal city of Alexandria to Cairo was hijacked and forced to divert to Cyprus, where the hijacker, who was described as "unstable", demanded to see his ex-wife.
He had claimed he was wearing an explosive vest, which turned out to be fake.
Last October, foreign governments issued travel warnings for Egypt and demanded a review of security at its airports after IS downed the Russian airliner with what it said was a bomb concealed in a soda can that had been smuggled into the hold.