A Russian plane carrying 224 passengers was "completely destroyed" after crashing in central Sinai, killing all those on board.
Authorities have reported that the Metrojet plane was "completely destroyed" with "all on board likely to have died".
The Egyptian search and rescue team dispatched to the scene was initially searching for survivors as "voices" could still be heard inside part of the plane, according to a security officer who told Reuters:
There is another section of the plane with passengers inside that the rescue team is still trying to enter and we hope to find survivors, especially after hearing pained voices of people inside.
The plane, understood to be a Metrojet from Russian airline Kogalymavia with flight number 9268, had left Egyptian resort Sharm el-Sheikh bound for St Petersburg. It had 217 passengers and seven members of crew on board.
It lost contact with Egyptian air traffic controllers and reportedly failed to make scheduled contact with Cyprus. Initially, conflicting reports claimed that the aircraft came in contact with Turkish air traffic control soon afterwards.
The Egyptian prime minister's office said Sherif Ismail had formed a "cabinet-level" crisis committee to deal with the crash.
Claims that Islamic State militants were responsible for the crash have been rejected by Russia's transport minister Maksim Sokolov, and Egyptian security sources have also denied any indications that the plane was shot down, reports news agency Reuters.
The plane, which left at 03.51 GMT, lost contact 23 minutes into its flight, according to plane tracker Flightradar24. According to the tracker, which reported losing signal with the airliner, the aircraft began making a steep descent just before signal was lost:
The airplane was due to land in St Petersburg at 12.10, according to Russia's aviation authority Rosaviatsiya.