The discovery of human remains, wreckage and passenger belongings from an EgyptAir plane that plunged into the Mediterranean Sea on Thursday added momentum to the quest to unravel the mystery of why Flight 804 from Paris to Cairo suddenly dropped from the sky, probably killing all 66 people aboard.

Without the bulk of the fuselage and flight recorder, the tragedy has offered few tangible clues but plenty of speculation that terrorists may have targeted the Airbus A320.

On Friday, Egyptian naval ships backed by U.S. and European search aircraft scoured the Mediterranean, concentrating the hunt on an area about 180 miles off the coast of the Egyptian city of Alexandria, according to an Egyptian military spokesman, a day after earlier reports of located debris were retracted. If more debris is located in the area in coming days, it could signal a major shift in the investigation into how the plane, traveling at a cruising altitude of 37,000 feet, could have suddenly swerved, flown in a circle, then plunged thousands of feet, losing contact with air controllers before vanishing.

READ: Wreckage of EgyptAir plane, body part found in Mediterranean

Experts now have a target zone to try to peer below the waves in hopes of finding the flight recorders and what remains of the fuselage. But the presumed crash site covers some of the deepest water in the Mediterranean, with a seabed basin that is more than 10,000 feet below the surface in some places. The currents are also strong, which could complicate efforts to pinpoint the wreckage.


In Athens, more details about the reported Egyptian finds were given by Greek Defense Minister Panos Kammenos, who said a seat, luggage and "a body part" were spotted. The European Space Agency, meanwhile, said a satellite detected a possible oil slick in the same area. Greek state television said the recoveries were made about 115 miles from the plane's last tracked position.

A day after a top official in Egypt said that terrorism appeared more likely than a catastrophic technical malfunction, French Foreign Minister Jean-Marc Ayrault said on France-2 television that there is "absolutely no indication" of the cause of the crash. No group has claimed responsibility for the fallen plane.

U.S. officials also urged caution on drawing conclusions about the cause of the crash. Analysts at the CIA and other agencies, meanwhile, have worked with foreign counterparts to scrutinize the flight's passenger list and crew roster. Three French civil-aviation experts arrived in Cairo on Friday to assist with the investigation, reported Egypt's flagship state-owned newspaper, Al-Ahram.

Meanwhile, the Aviation Herald, an industry publication, reported on its website that sensors detected smoke in a lavatory near the cockpit, suggesting a fire onboard before the aircraft went down. The information was transmitted through the plane's Aircraft Communications Addressing and Reporting System, the publication said.

The discovery of the debris and passenger remains diminished already slim hopes of finding any survivors. There were about a dozen nationalities on board, with Egypt and France suffering the greatest losses. In Cairo on Friday, hundreds of relatives and friends of the missing gathered in mosques for memorial services, offering solemn prayers and tears.

The plane left Paris at 11:09 p.m. Wednesday. It flew across northern Italy and into Greek airspace, where air traffic controllers later noted that the plane's pilot "was in good spirits" before entering Egyptian airspace. Minutes later, the plane veered violently to the east, dropping from 37,000 feet to 15,000, according to Kammenos. At one point, the plane made a "360-degree turn" before disappearing from radar and crashing into the Mediterranean.

The disappearance of Flight 804 was Egypt's third major air incident in eight months, further eroding confidence in the safety of the country's air travel and delivering another blow to government efforts to revive a struggling economy and tourism sector. In October, the Islamic State's affiliate in Egypt asserted responsibility for bringing down a Russian charter flight over the Sinai Peninsula with a bomb smuggled aboard, killing all 224 people on the plane. In March, an EgyptAir flight from Alexandria was hijacked and diverted to Cyprus by a 59-year-old Egyptian man wearing a fake explosives belt. He later surrendered, and all hostages were released.

In a sign that the Flight 804 crash could have serious economic ramifications, the Egyptian stock exchange plunged on Thursday - its last trading day of the week - recording more than $300 million in losses. And the Egyptian newspaper Al-Wafd quoted an adviser to the country's tourism minister as saying the government expected an industry downturn following the crash - "due to fears of traveling with EgyptAir."

On Friday, Egyptian President Abdel Fatah al-Sissi expressed condolences to the families of the passengers. In a statement, his office said that Sissi, "with utmost sadness and regret, mourns the victims on board the EgyptAir flight who were killed."

The tragedy was particularly felt by Osman Abu Laban. The Lebanese film director's aunt and uncle, their son and the son's wife were aboard Flight 804. On Friday, in a post on his Facebook page, Laban, who lives in Egypt, announced funeral prayers at a Cairo mosque for his lost relatives. "Oh Lord have mercy and forgive them and make their final resting place a paradise," he wrote.