A Russian airliner has crashed in central Sinai killing all 224 people on board, Egyptian officials have said.

The Airbus A-321 had just left the Red Sea resort of Sharm el-Sheikh, bound for the Russian city of St Petersburg.

Wreckage was found in the Hasana area and bodies removed, along with the plane's "black box". An official described a "tragic scene" with bodies of victims still strapped to seats.

Russian President Vladimir Putin has declared Sunday a day of mourning.

He has ordered an official investigation into the crash, and for rescue teams to be sent to the crash site.

Egyptian officials said 214 of the passengers were Russian and three Ukrainian.

A commission headed by Russian Transport Minister Maksim Sokolov is to leave for Egypt on Saturday afternoon.

A criminal case has also been opened against the airline, Kogalymavia, for "violation of rules of flight and preparation for them", Russia's Ria news agency reported.

Oksana Golovin, a spokeswoman for the airline, said the company did not see any grounds to blame human error.

She told a press conference that the pilot had 12,000 hours of flying experience. Kogalymavia did not yet know what caused the crash, she said, but the plane was fully serviced.

Police are reported to be searching the company's offices.

Russian authorities say the plane was carrying 217 passengers, 138 of them women and 17 children aged between 2 and 17. Most were tourists. There were seven crew on board.

Egyptian officials investigating the scene said there were no survivors.

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.

Sudden altitude loss

Initially there were conflicting reports about the fate of the plane, some suggesting it had disappeared over Cyprus.

But the office of Egyptian Prime Minister Sharif Ismail confirmed in a statement that a "Russian civilian plane... crashed in the central Sinai".

Officials say up to 50 ambulances have been sent to the scene.

Access to the area is strictly controlled by the military and the terrain is difficult, correspondents say.

One official told Reuters news agency that at least 100 bodies had been found.

"I now see a tragic scene," the official said. "A lot of dead on the ground and many died whilst strapped to their seats."

The plane split in two, with one part burning up and the other crashing into a rock, he added.

The Egyptian cabinet said in a statement that flight KGL9268 left Sharm el-Sheikh at 05:58 local time (03:58 GMT)

It added that the aircraft went off the radar 22 minutes after take-off.

The flight had been due into St Petersburg's Pulkovo airport at 09:10 GMT.

Kogalymavia airline

• Also known as KolAvia
• Founded in 1993
• Carried out regular and charter flights to other parts of Russia from the western Siberian towns of Kogalym and Surgut, and helicopter flights for the oil and gas industry
• Rebranded as Metrojet in 2012
• After takeover by tourism company TH&C in 2013, began flights to international destinations popular with Russian holiday-makers
• Currently has fleet of seven Airbus-321s and two Airbus-320s

Egypt's civilian aviation ministry said the plane had been at an altitude of 9,450m (31,000ft) when it disappeared.

Live flight tracking service Flight Radar 24's Mikail Robertson confirmed the altitude.

He told the BBC that the plane started to drop very fast, losing 1,500 metres in one minute before coverage was lost.

Aviation official Ayman al-Mukadem said the pilot had reported technical difficulties before the plane went missing, the Associated Press reported.

The BBC's Orla Guerin in Cairo says it is likely there will be speculation about militant involvement in the incident - Sinai has an active militant network, with local Jihadis who have allied themselves to so-called Islamic State.

But the aircraft's altitude suggests that it could not have been struck from the ground, she adds.

Local weather observations in the vicinity of the rescue scene suggest relatively benign conditions.