LATEST: Egypt's military said its search teams found wreckage on Friday from the EgyptAir plane that crashed in the Mediterranean with 66 people on board, AFP said.
"Egyptian aircraft and navy vessels have found personal belongings of passengers and parts of the wreckage 290 kilometres (180 miles) north of Alexandria," its spokesman said on his Facebook page.
The navy has also found some of the passengers' belongings and is sweeping the area looking for the plane's black box, the military said in a statement.
A body part, seats and one or more items of luggage were found Friday by crews searching for the wreckage of an EgyptAir passenger jet that crashed in the Mediterranean, Greece's defence minister said.
"A few hours earlier we were informed (by Egyptian authorities) that a body part, two seats and one or more items of luggage were found in the search area" north of the coastal Egyptian city of Alexandria, Panos Kammenos told a news conference.
He said other aircraft participating in the search had "allegedly reported more findings in another area, but currently we have no official confirmation that they belong to the plane in question."
The EgyptAir plane carrying 66 people disappeared from radar screens early Thursday, taking two sharp turns before plunging 22,000 feet into the Mediterranean Sea, according to Greek officials.
Egyptian President Adbel Fattah al-Sisi offered condolences for those on board, amounting to Cairo's official confirmation of their deaths.
Although fingers pointed towards Daesh who blew up another airliner over Egypt just seven months ago, no group had claimed responsibility more than 24 hours after the disappearance of flight MS804, an Airbus A320 that was flying from Paris to Cairo.
Debris spotted in the Mediterranean Sea.
Flight attendant Samar Ezz Eldin, 27. (Facebook)
Flight captain Mohamed Said Aly Aly Shakeer. (Facebook)
EgyptAir Vice Chairman Ahmed Adel said the debris found in the Mediterranean Sea was not from Flight 804.
Greek rescue workers found lifevests and bits of plastic floating in the Mediterranean after an EgyptAir jet carrying 66 passengers and crew from Paris to Cairo disappeared from radar.
"We stand corrected on finding the wreckage because what we identified is not a part of our plane. So the search and rescue is still going on," Adel told CNN.
Air-sea search intensifies for missing EgyptAir plane
A massive search was under way for an EgyptAir plane that disappeared over the Mediterranean with 66 people on board, with suspicions swiftly focusing on a terrorist motive.
Egypt's aviation minister said that while it was too soon to say why the Airbus A320 flying from Paris to Cairo had vanished from radar screens, 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 Daesh group over Egypt last October that killed all 224 people on board.
The plane disappeared between the Greek islands and the Egyptian coast in the early hours of Thursday morning, without its crew sending a distress signal.
Greek Defence Minister Panos Kammenos said the aircraft had swerved sharply twice in Egyptian airspace before plunging 22,000 feet (6,700 metres) and disappearing from radar screens.
Both Egypt and Greece dispatched aircraft and naval vessels on a major search mission. They were expected to be joined by French teams, while the US sent a surveillance plane to help with the operation.
Egypt's President Abdel Fattah al-Sisi demanded an "intensified search" for the aircraft after reports that wreckage from the plane had been found were retracted.
EgyptAir initially said on its Twitter account that the Egyptian authorities had recovered wreckage from the missing aircraft but the head of the Greek air safety authority told AFP that debris found close to the area where the jet went down did "not come from a plane".
French President Francois Hollande said the plane had "crashed", as authorities in both Paris and Cairo opened investigations.
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.
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.
No distress call
In the United States, White House spokesman Josh Earnest said "it's too early to definitively say what may have caused this disaster".
The catastrophe also entered the US presidential election campaign, where national security is shaping up a prominent issue.
Presumptive Republican presidential nominee Donald Trump said it appeared to be "yet another terrorist attack," adding "When will we get tough, smart and vigilant?"
His likely Democratic opponent Hillary Clinton agreed that it "does appear that it was an act of terrorism" and "once again shines a very bright light on the threats that we face from organised terror groups".
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 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 been scattered across a wide area.
EgyptAir's 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.
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.