An Airbus A321 operated by a Russian airline crashed after taking off from the Red Sea resort of Sharm el-Sheikh.
There were conflicting reports about what happened to the aircraft, which was carrying more than 200 Russian tourists on a flight to St Petersburg.
The aircraft was operated by the small Russian airline Kogalymavia, based in western Siberia. Latest reports say it was carrying 217 passengers and seven crew.
A “Russian civilian plane… crashed in the central Sinai”, the office of Egyptian prime minister Sharif Ismail said in a statement.
The Russian aviation authority said the aircraft failed to make scheduled contact with Cyprus air traffic control 23 minutes after take-off and disappeared from the radar, the BBC reported.