Breaking news alert, posted at 2:11 a.m. PT on Friday
Egyptian armed forces say they found debris from EgyptAir Flight 804 in the Mediterranean on Friday, according to military spokesman Brig. Gen. Mohammad Samir.
Passenger belongings and parts of the aircraft were found 180 miles (290 kilometers) north of the coastal city of Alexandria, according to a statement from the armed forces.
"Egyptian aircraft and naval vessels were able to locate on Friday morning 20 May 2016 some personal belongings of passengers as well as parts of the wreckage 290 km north of Alexandria area," the statement said. "The searching, sweeping and the retrieval process is underway."
Previous story, posted at 12:38 a.m. PT on Friday
The search for EgyptAir Flight 804 entered a second day after the jetliner vanished over the Mediterranean with 66 people aboard.
The plane was carrying 56 passengers and 10 crew members when it left Paris' Charles de Gaulle Airport for Cairo late Wednesday night.
It disappeared from radar early Thursday as it flew to Cairo -- what should have been about a 3½-hour flight.
Authorities said it likely crashed into the sea, but the reason why remains unclear. Weather conditions were clear at the time.
The Airbus A320 "swerved and then plunged" before descending into the Mediterranean, Greek Defense Minister Panos Kammenos said.
Debris not from plane
The airline's vice chairman said the wreckage of the plane had been found at sea, but those reports turned out to be false.
When searchers got close to the debris, they realized it was not from the missing airliner, Ahmed Adel said Thursday.
"We stand corrected on finding the wreckage because what we identified is not a part of our plane," Adel told CNN. "So the search and rescue is still going on."
What went wrong?
While no theory has been completely ruled out, speculation on what caused the flight to crash centered on the possibility of a terror attack.
At some point before dropping off radar, the plane swerved 90 degrees to the left and then made a 360-degree turn to the right before plunging first to 15,000 feet, then 10,000 feet, Greek officials said.
"It's very difficult to come up with a scenario that jibes with some sort of catastrophic failure. (The evidence so far) leads us down the road to a deliberate act," said Miles O'Brien, a CNN aviation analyst.
Egyptian officials pointed to technical failures and terror as possible explanations.
"But if you analyze this situation properly, the possibility of having a different action aboard, of having a terror attack, is higher than having a technical problem," said Sharif Fathi, the nation's aviation minister.
French officials urged caution, saying it's still too early to draw conclusions.
"All assumptions are reviewed but none is favored," Foreign Minister Jean-Marc Ayrault told France 2 network Friday. "We have absolutely no indication on the causes of this event."
He said his Egyptian counterpart Sameh Shoukry was not leaning toward terrorism as the cause of the crash.
"He said he wanted all possibilities to be examined," Ayrault told France 2.
Ayrault defended security measures at the Paris airport, saying they have been intensified since the November terror attacks.
Controllers tried to reach pilot
Shortly before the aircraft was scheduled to exit Greek airspace early Thursday, controllers tried to reach the pilots to transfer control to Cairo authorities. Despite repeated attempts, they received no response, Greece's Aviation Authority said.
Radar soon lost the plane's signal, just after it entered Egyptian airspace, the authority said.
Passengers and crew
Most of the passengers are Egyptian -- 30 in all. But also aboard are 15 French citizens, including an infant. There were also passengers from Iraq, Britain, Belgium, Kuwait, Saudi Arabia, Sudan, Chad, Portugal, Canada and Algeria, according to the Egyptian aviation minister.
Canada said two of its citizens were on the plane.
Australian Foreign Minister Julie Bishop said the British passenger had Australian citizenship as well. It is unclear whether any other passengers were dual citizens.
Greece, France, the United States and other nations involved are searching about 130 nautical miles southeast of Karpathos, Greek aviation officials said.
The U.S. Navy has deployed a P-3 Orion aircraft to assist in the search. Egypt's military was also involved, and France said it tasked a surveillance plane to help.
As crews searched, somber relatives gathered in Cairo and Paris airports, seeking word on their loved ones.
-- The pilots have been identified as Mohamed Said Shoukair, who was the plane's captain, and first officer Mohamed Mamdouh Ahmed Assem, according to an official close to the investigation and a security source.
-- The head flight attendant was identified as Mirvat Zaharia Zaki Mohamed.
-- The plane's captain had about 6,000 flying hours, Adel said. Maintenance checks on the plane had reported "no snags."
-- Checks of the passenger manifest have so far resulted in no hits on terror watch lists, officials with knowledge of the investigation said.
-- An initial theory is that the plane was downed by a bomb, two U.S. officials told CNN. Officials said the theory could change, with one senior administration official cautioning it is not yet supported by a "smoking gun."
-- The jet had routine maintenance checks in Cairo before it left for Paris, the airline said. Earlier Wednesday, the jet was also in Eritrea and Tunisia, data from flight tracking websites show.
-- The plane has been part of EgyptAir's fleet since November 2003, according to Adel.