The Airbus A-321 had just left the Red Sea resort of Sharm el-Sheikh, bound for the Russian city of St Petersburg.
The plane wreckage has been found in the Hassana area. It disappeared from radar screens when travelling at 31,000ft, Egyptian officials said.
Egyptian officials said most on board are likely to have died.
The plane was operated by the small Russian airline Kogalymavia, based in western Siberia.
Russian authorities say it was carrying 217 passengers, 17 of them children, and seven crew. Most were Russian tourists.
Initially there were conflicting reports about the fate of the plane, some suggesting it had disappeared over Cyprus.
The office of Egyptian PM Sharif Ismail confirmed in a statement that a “Russian civilian plane… crashed in the central Sinai”.
It added that Sharif Ismail had formed a crisis committee to deal with the crash.
Media reports say at least 40 ambulances have been sent to the scene.
The Russian aviation authority Rosaviatsiya said in a statement that flight 7K 9268 left Sharm el-Sheikh at 06:51 Moscow time and had been due into St Petersburg’s Pulkovo airport at 12:10.
The authority added that the aircraft failed to make scheduled contact with Cyprus air traffic control 23 minutes after take-off and disappeared from the radar.
Egypt’s civilian aviation ministry said the plane had been at an altitude of 31,000ft when it disappeared.
Live flight tracking service Flight Radar 24’s Mikail Robertson confirmed the altitude.
A centre to help relatives of the passengers has been set up at Pulkovo airport, Tass news agency quoted St Petersburg city officials as saying.
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