An Egyptair plane crashed Thursday in the Mediterranean Sea with 66 people on board amid suspicions that a terrorist act was involved.
Egyptian authorities said an extensive search was under way jointly with Greece for the wreckage of the Airbus A320 that went missing earlier in the day while flying from Paris to Cairo.
Search teams found two large objects in waters off Egypt suspected to belong to an Egyptair passenger plane, Greek state television reported, citing military staff.
The suspected Egyptair debris was found approximately 420 kilometres south-east of the Greek island of Karpathos, according to the report.
Egypt dismissed the report as untrue.
"Egyptair contacted the bodies concerned in Greece, which did not confirm the validity of this information," the airliner said in a statement.
An Egyptian official suggested that the MS804 flight might have crashed due to a terrorist act.
"The situation may indicate that the likelihood of a terrorist work is far higher than the likelihood that the plane developed a technical failure," Egyptian Civil Aviation Minister Sherif Fathy said in Cairo. "But we have to wait for investigations."
Fathy added that Egypt and Greece were widening the scope of search for the wreckage.
Egypt asked several countries to assist in the research and rescue efforts, he said, mentioning only Greece.
"It is expected that the area of search will be large because the plane disappeared while flying at the height of 37,000 feet (11,300 metres)."
US President Barack Obama was briefed on the incident by his counterterrorism advisor and directed US officials to offer support and assistance.
Fathy retracted an earlier statement by Egyptair that the Egyptian military search teams received a distress call from the emergency mechanisms of the plane almost two hours after its departure from Paris.
The plane went missing at 2:30 am (0030 GMT), some 45 minutes before it was expected at Cairo airport, Egyptair said.
The jet carrying 56 passengers, seven crew members and three security officers took off from Charles de Gaulle Airport in the French capital late Wednesday, the Egyptian national carrier said.
The passengers included 30 Egyptians, 15 French nationals, two Iraqis and one each from Britain, Belgium, Kuwait, Saudi Arabia, Sudan, Chad, Portugal, Algeria and Canada, according to the airline. Three children were on board.
The pilots of the plane did not contact Greek aviation authorities after leaving Greek airspace, the head of the country's Civil Aviation Authority told Greek broadcaster Skai.
"When they initially flew over the island of Kea, they made normal contact and did not mention any problems," Konstantinos Lintzarakis said.
The aircraft subsequently flew through Greek airspace towards Egypt, but the pilots did not again make contact - as is customary - when they left Greek airspace south of the Greek island of Karpathos and south-east of Crete.
Egypt and France said they had opened separate investigations into the accident that comes nearly seven months after a Russian plane crashed in Egypt's troubled Sinai, killing all 224 people on board.
Egyptair named the pilot of Thursday's crashed plane as Mohammed Said Ali Shaqir and said he had over 6,000 hours of flights logged, more than 2,000 of them on Airbus A320s. The co-pilot had 2,766 flight hours logged, the company said.
The plane was delivered to the operator in 2003, its manufacturer Airbus said, adding that it had accumulated some 48,000 flight hours.
France has offered Egyptian and Greek authorities help in their search operations for the aircraft, with President Francois Hollande saying the plane had crashed.
Hollande agreed in a phone call with his Egyptian counterpart Abdel-Fattah al-Sissi on "coordination and cooperation" between their countries to unravel circumstances surrounding the accident, Egyptian state television reported.
"We are mobilized and at the disposal of the Egyptian authorities, with our military resources - our planes, our boats - to help with the search for the plane," French Foreign Minister Jean-Marc Ayrault said. At Cairo airport, families who had been waiting to meet passengers of the plane were brought to a private room and were being attended to by medical staff, officials said.
The crash comes in the wake of two other incidents involving Egyptian aviation.
In March, a man used a fake explosive belt made of mobile phone covers and cables to force an Egyptair flight to land in Cyprus.
In October 2015, a Russian passenger jet broke up in mid-air shortly after take-off from the resort of Sharm el-Sheikh in Egypt's Sinai peninsula, killing all 224 people on board. Russian authorities said that the incident was caused by a bomb. The Islamic State extremist group, which operates in Sinai, claimed responsibility and published a photograph of a soft drink can which it said had been filled with explosives and smuggled onto the flight.