A Russian airliner carrying 224 people crashed in a mountainous area of Egypt's Sinai Peninsula yesterday, killing everyone on board, officials said.
It was one of the deadliest incidents involving Airbus aircraft over the past decade.
The Islamic State (IS) group affiliate in Egypt claimed it downed the plane, without saying how.
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.
"Unfortunately, all passengers of Kogalymavia flight 9268 Sharm el-Sheikh-Saint Petersburg have died. We issue condolences to family and friends," the Russian embassy in Cairo said.
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.
President Abdel Fattah al-Sisi and his French counterpart Francois Hollande sent Moscow their condolences.
Russia's emergency ministry published a list of names of the passengers, ranging in age from a 10-month-old girl to a 77-year-old woman.
A senior Egyptian aviation official said the charter flight was flying at 30,000 feet when communication was lost.
At Saint Petersburg's Pulkovo airport, family members awaited news.
Ella Smirnova, 25, said she had been there to meet her parents.
"I spoke to them last on the phone when they were already on the plane, and then I heard the news.
"I will keep hoping until the end that they are alive, but perhaps I will never see them again."
A senior Egyptian air traffic control official said the pilot told him in their last communication that he had radio trouble.
Russian aviation official Sergei Izvolsky told Interfax news agency the aircraft took off from Sharm el-Sheikh at 5:51am (0351 GMT).
He said it did not make contact as expected with Cyprus air traffic control.
Kogalymavia, which operates under the name Metrojet, says it has two A320s and seven A321s, and that it carried 779,626 passengers in the first nine months of 2015, according to the Russian aviation agency Rosaviatsia.
Russia has a dismal air safety record, with charter operators often under pressure to book to capacity on ageing jets in an attempt to cut costs.
Kogalymavia is a small regional carrier that flies mostly international charter services.
The crash is likely to raise renewed concerns about the safety of air travel in a country with an ageing fleet of airliners.
The last major air crash in Egypt was in 2004, when a Flash Airlines Boeing 737 plunged into the Red Sea after taking off from Sharm el-Sheikh.
All 148 people on board, most of them French, died.
Millions of tourists, including many Russians, visit the resort, one of Egypt's major attractions for its pristine beaches and scuba diving.
