It could take months to determine the cause of a Russian plane crash in Egypt that killed all 224 people on board, Egyptian President Abdel Fattah al-Sisi warned, as examination began on the holiday flight's black boxes.
"This is a complicated matter and requires advanced technologies and broad investigations that could take months," Sisi said in a televised speech on Sunday.
Egyptian analysts began examining the contents of the two "black box" recorders recovered from the airliner although the process, according to a civil aviation source, could take days. However, Russian Transport Minister Maxim Sokolov told Russia 24 television that this work had not yet started.
Flight KGL9268 crashed in remote central Sinai shortly after daybreak on Saturday, about 25 minutes after take-off from the Egyptian resort region of Sharm el-Sheikh. The Airbus A-321, operated by Russian airline Kogalymavia under the brand name Metrojet, was en route to St Petersburg, Russia.
A Russian aviation official said on Sunday that it appeared the plane "broke up in the air."
Viktor Sorochenko, an official with the Intergovernmental Aviation Committee (IAC), cautioned, however, that it was too early to make assumptions based on this finding after he made the comments following a visit to the crash site with other investigators. The Moscow-based IAC represents governments of the Commonwealth of Independent States, which groups Russia and other former Soviet republics.
Alexander Neradko, head of Russia's federal aviation agency, similarly said investigators believe the plane disintegrated at a high altitude because the plane's fragments have been found scattered over a large area. He also stressed that the investigation into the cause of the crash was ongoing.
Russia's Federal Transportation Inspection Service said Sunday it had barred Metrojet from flying Airbus A321s pending the outcome of the crash investigation.
Metrojet said in a statement that the move is standard procedure, and the airline is "sure of the technical safety of our planes and high professionalism of the pilots." In a separate statement, the airline said it had full faith in the expertise of the plane's pilot, identified as Valery Nemov. The airline said Nemov had thousands of hours of experience.
The doomed plane came down in an area that has witnessed fierce fighting between Egyptian soldiers and Islamist insurgents. Officials, however, have dismissed claims the plane was shot down, saying militants lacked the weapons to do it.
Still, several airlines opted to suspend flights over Sinai pending further clarity over what caused the plane crash. Emirates — the Middle East's largest airline — announced it was stopping flights over Sinai on Sunday, mirroring moves a day earlier from Air France and Lufthansa, according to The Associated Press. Fly Dubai also announced Sunday that it would re-route its flights. Carriers from Qatar, Bahrain and Kuwait also said they would re-route flights away from the area as a precaution.
Germany's Ministry of Transportation issued a warning about routing flights through the south of Sinai. The ministry already had a previous warning in place about flying through the north of Sinai.
Lingering suspicions were also evident in St. Petersburg, where hundreds of worshippers lit candles, laid flowers and prayed for the victims at the Kazan cathedral.
"Everyone thinks it was ... these Islamic fundamentalists," Mikhail Kudryavtsev told the AP.
Andrei Bryatov, 30, who knew a family that was on the flight, said he would leave the determination about the cause of the crash to investigators. "I don't know what happened. I leave it to the experts. The truth will be what they say," Bryatov said.
The tragedy has plunged Russia into mourning. Flags flew at half-mast over the Kremlin as memorials to the victims sprouted both in and outside the country and Pope Francis joined world leaders offering condolences for the tragedy.
Egypt's government said that 163 bodies had been recovered from the scene as of Sunday morning, adding that recovery efforts were ongoing. Bodies of 130 of the victims were being loaded onto Russian military planes Sunday bound for St Petersburg, according to the Russian Embassy in Egypt.
DNA samples from 146 relatives of victims had been collected for comparison to identify the victims, the Investigative Committee of the Russian Federation said in a statement.
Those on board the doomed flight included 214 Russians, at least three Ukrainians and one Belarusian, most returning from the Red Sea, popular with Russians seeking winter sun.
The wreckage was found in a desolate area of stony ground. Rescuers had collected the colorful suitcases of the passengers into a pile. A pink child's sandal decorated with white flowers lay among the debris, a reminder that 17 children were among those killed as they headed home from their holidays.
Parts of the wreckage were blackened and charred, with one section forming heaps of twisted metal, although the blue Metrojet logo was still visible on its broken tail fin.
As the Russian investigators moved slowly across the site, Egyptian military helicopters buzzed overhead, combing the wider area for debris - or bodies - not yet found.
The Russian federation's Investigative Committee also said it had collected documentation concerning the plane's upkeep, flight information and air traffic control reports. The committee has also questioned maintenance workers and crew who attended to the Airbus on the day before the crash.
The committee was working to obtain paperwork related to the crew's pre-flight examinations and documentation about the plane's hardware, it said.
An Egyptian official who said he inspected the plane with others on Saturday before it went down told the AP that the jet seemed to be in good condition.
"We are all shocked. It was a good plane. Everything checked out in 35 minutes," the official said on the condition of anonymity because he was not authorized to speak to the media. The closest the plane came to being in trouble, he said, was three months ago when the pilot aborted takeoff halfway through because of a system error.
Russia's Emergencies Ministry said it had sent more than 70 people to Egypt to help search the site and assist the investigation, with rescue teams focused on coming an area larger than 6 square miles.
France's civil aviation safety agency, BEA, said it was sending two investigators to Egypt along with six technical advisers from Airbus. The team will be joined by two investigators from Germany's Federal Bureau of Aircraft Accident Investigation, BEA said in a statement.
The co-pilot's wife told Russia's state-controlled NTV that her husband complained about the plane before taking off on the doomed flight.
"He complained before the flight that the technical condition of the aircraft left much to be desired," the woman, identified as Natalya Trukhacheva, told NTV.
Metrojet said in a statement that the airline's planes are "properly serviced and receive pre-flight maintenance."
"We have a personal interest in their serviceability, because our lives depend on it, too," the airline said.
- Reuters contributed to this report.