Egypt says its navy has found human remains, wreckage and the personal belongings of passengers floating in the Mediterranean, confirmation that an EgyptAir jet had plunged into the sea with 66 people on board.
President Abdel Fattah al-Sisi on Friday offered condolences for those on board, amounting to Egypt's official acknowledgement of their deaths, although there was still no explanation of why the Airbus had crashed.
"The Egyptian navy was able to retrieve more debris from the plane, some of the passengers' belongings, human remains, and plane seats," the Civil Aviation Ministry said in a statement.
The navy was searching an area about 290 km north of the port city of Alexandria, just south of where the signal from the plane was lost early on Thursday.
There was no sign of the bulk of the wreckage, or of a location signal from the "black box" flight recorders.
A European satellite spotted a 2km-long oil slick in the Mediterranean, about 40km southeast of the aircraft's last known position, the European Space Agency said.
Egyptian Prime Minister Sherif Ismail said it was too early to rule out any cause for the crash. The aviation minister said a terrorist attack was more likely than a technical failure, but offered no evidence.
Although early suspicion has centred on Islamist militants who blew up another airliner over Egypt seven months ago, no group had claimed responsibility more than 36 hours after the disappearance of flight MS804, an Airbus A320 flying from Paris to Cairo.
CNN reported on Friday that flight data, from an automatic system called the Aircraft Communications Addressing and Reporting System (ACARS), suggested there were smoke alerts aboard the EgyptAir jet minutes before it crashed.
ACARS routinely downloads flight data to the airline operating the aircraft.
Two US officials told Reuters an electronic sensor system had detected some kind of disturbance outside the jet around the time investigators believe it began falling from cruising altitude. They could not confirm CNN's report that smoke had been detected inside the cabin.
One of the officials said the disturbance outside the aircraft may have been caused by its sudden and rapid break-up, but also could have been generated by some kind of mechanical fault or accident or a possible explosion or attack.
The two officials asked for anonymity when speaking about the still-evolving investigation.
Jihadists have been fighting Egypt's government since President Sisi toppled an elected Islamist leader in 2013. In October the Islamic State group claimed responsibility for blowing up a Russian airliner that exploded after taking off from an Egyptian tourist resort. Russian investigators blamed a bomb smuggled on board.
That crash devastated Egypt's tourist industry, one of the main sources of foreign exchange for a country of 80 million people, and another similar attack would crush hopes of it recovering.
The plane vanished just as it was moving from Greek to Egyptian airspace control. Greek Defence Minister Panos Kammenos said it had swerved radically and plunged from 11,278m to 4572m before vanishing from Greek radar screens.
Officials from several US agencies say a US review of satellite imagery so far hasn't produced any signs of an explosion.