The aircraft disappeared with 56 passengers and 10 crew on board
EgyptAir has confirmed the wreckage of missing Flight MS804 has not been found, just hours after saying debris discovered in the Mediterranean belonged to the aircraft.
An airline official told CNN: "We stand corrected."
It comes after multiple reports in Greece and Egypt claimed debris including floating objects and life vests had been found.
EgyptAir had earlier released a statement expressing its "deepest sorrow", saying it had received an official letter from the Egyptian Ministry of Foreign Affairs confirming the wreckage had been found.
"Family members of passengers and crew have been already informed and we extend our deepest sympathies to those affected," the statement added.
"Meanwhile, the Egyptian investigation team, in cooperation with the Greek counterpart, are still searching for other remains of the missing plane."
Greek officials have also denied the wreckage found in the Mediterranean belongs to the aircraft.
The aircraft disappeared with 56 passengers and 10 crew on board.
Egyptian Civil Aviation Minister Sherif Fathy said the plane, which was en route from Paris to Cairo, is more likely to have been brought down by a "terror attack" than a technical fault.
French President Francois Hollande said "unfortunately the information we have ... confirms to us the plane came down and is lost".
Greek defence minister Panos Kammenos said the aircraft was in Egyptian airspace and flying at 37,000ft when it made "sudden swerves" and plunged to 15,000ft.
He said it swerved "90 degrees left and then 360 degrees to the right" before vanishing.
Authorities are examining CCTV footage at Charles de Gaulle Airport - and investigating an account from the captain of a merchant ship who reported seeing a "flame in the sky" some 130 nautical miles south of Karpathos.
Mr Fathy said there were no known security issues with the passengers who boarded the jet, but further checks were being made.
Flight MS804 departed from the French capital at 10.09pm Irish time. The airline said the plane lost contact with radar at 1.30am. It was last in touch 10 minutes earlier.
At that stage the Airbus A320, which was 13 years old and had logged 48,000 flight hours, was about three hours and 40 minutes into the four-hour journey.
Security analyst Tom Clonan said the disappearance is very unsettling following the recent spate of aviation disasters.
He told Newstalk Lunchtime: "I would be very concerned given the timing of this disappearance, the location and also the route that the aircraft took - prior to the Paris-Cairo leg, it had been in Tunisian airspace."
Military search and rescue teams picked up an automated signal from the plane's emergency beacon at 3.26am Irish time - around 80 minutes after it was supposed to land in Cairo. It is thought this may have been triggered on impact.
Thirty Egyptians, 15 French, two Iraqis, a Belgian, a Briton, a Kuwaiti, a Saudi, a Sudanese, a Chadian, an Algerian, a Portuguese and a Canadian are among the passengers which also include one child and two babies.
Greek and French boats and planes have joined special teams from the Egyptian armed forces in the search for the jet. Greece also has a submarine on standby, while Britain and the US have offered their support too.
including 1 child and 2 infants in addition to 3 EGYPTAIR security personnel and 7 cabin crew with a total of 66 persons on board.— EGYPTAIR (@EGYPTAIR) May 19, 2016
Greek civil aviation authorities said the jet disappeared off its radar two minutes after leaving its airspace. Prior to that, its air traffic controllers spoke to the pilot who reported no problems.
However, just before the handover to Cairo airspace, calls to the plane went unanswered.
Ahmed Abdel, the vice-chairman of EgyptAir holding company, told CNN there had been no distress calls from the plane.
The New York Times quoted Ehab Mohy el-Deen, the head of Egypt's air navigation authority, as saying: "They did not radio for help or lose altitude. They just vanished."
The airline said the plane's pilot had flown 6,275 hours - including 2,101 hours on the same model - while the co-pilot had done 2,766 hours.
A crisis centre offering support to the distressed families of loved ones on board has been set up at Cairo International Airport.