The Islamic State (IS) group affiliate in Egypt claimed it downed the plane, without saying how, AFP reports.
Egyptian Prime Minister Sharif Ismail expressed doubt about the claim, saying “experts confirmed that a plane cannot be downed at such an altitude”, and Russian Transport Minister Maksim Sokolov said the claim “cannot be considered accurate”.
Germany’s Lufthansa and Air France said they would halt flights over Sinai until the reasons behind the crash became clear.
The Airbus A321 with 214 Russian and three Ukranian passengers and seven crew, had taken off from the Red Sea resort of Sharm el-Sheikh in south Sinai bound for Saint Petersburg.
It lost contact with air traffic control 23 minutes later.
The wreckage was found roughly 100 kilometres (60 miles) south of the North Sinai town of El-Arish, Egyptian officials said.
Debris and bodies was spread over an area of between six and eight square kilometres (two and a half to just over three square miles).
The aircraft’s black box had been retrieved and sent for analysis, Ismail said.
The IS affiliate waging an insurgency in the Sinai claimed that “the soldiers of the caliphate succeeded in bringing down a Russian plane”.
It said this was in revenge for Russian air strikes against IS in Syria.
Three military experts said IS in Sinai does not have surface-to-air missiles capable of hitting a plane at high altitude.
But they could not exclude the possibility of a bomb on board or a surface-to-air missile strike if the aircraft had been descending to make an emergency landing.
The Kremlin said President Vladimir Putin ordered rescue teams dispatched to Egypt.
Russian experts would take part in the Egyptian-led investigation, Ismail said.