Egypt's president said a Russian plane that crashed in Sinai last year was downed by terrorists in the first official indication from the country that foul play lay behind the disaster.
"Has terrorism ended? No, it has not, but it will if we unite. Whoever downed the Russian plane, what did he mean? He meant to hit tourism, and to hit relations with Russia," Abdel Fattah al-Sisi said.
Moscow stopped all civilian flights to Egypt, a popular destination for Russian tourists, after the Russian plane crashed in Sinai on 31 October, killing all 224 people aboard.
Russia said a bomb destroyed the airliner.
The official Egyptian confirmation that a bomb brought down the Airbus A-321 jet could expose Egypt to compensation payments to the families of the victims.
The so-called Islamic State militant group, whose Egyptian affiliate is waging an insurgency in the Sinai peninsula, said it smuggled the explosive aboard inside a soft drink can.
But an Egyptian-led investigation had said it has yet to find evidence of foul play.
An EgyptAir mechanic whose cousin joined IS in Syria is suspected of planting a bomb on the plane, sources said last month.
A senior security official at the airline denied that any of its employees had been arrested or were under suspicion, and an Interior Ministry official also said there had been no arrests.
The crash has called into question Egypt's campaign to eradicate Islamist militancy and damaged its tourism industry, a cornerstone of the economy.
Islamist militants have stepped up attacks on Egyptian soldiers and police since Mr Sisi toppled freely elected Islamist President Mohammed Mursi in 2013 after mass protests against his rule. Hundreds have been killed.