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The Russian plane that crashed over Egypt's Sinai Peninsula "broke up in the air," a Russian aviation official said on Sunday, as airlines halted flights over the region while waiting for clarity on what downed the airliner.

Viktor Sorochenko, an official with the Intergovernmental Aviation Committee, said it appeared that the Airbus A321 operated by Metrojet broke up midair before crashing Saturday with 224 people on board. Sorochenko said 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 Sunday, according to Reuters.

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.

Photos: Investigators Search Crash Site of Russian Plane

No one aboard the flight survived after the plane traveling from Sharm el-Sheikh to St. Petersburg crashed shortly after takeoff in the Sinai Peninsula.

Russia's Federal Transportation Inspection Service said Sunday it has 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.

Egyptian Abdel Fattah el-Sisi warned against speculating about the cause of the crash, saying in televised remarks that the investigation could take months.

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.

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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.

Egyptian paramedics loaded the bodies of plane crash victims Saturday. KHALED DESOUKI / AFP — Getty Images

Most of the victims on the doomed plane were Russian and the tragedy plunged the nation into mourning. Flags flew at half-staff 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, 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.

The 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.

Forensic experts from Russia were seen entering Cairo's main morgue on Sunday while planes waited at Cairo airport to transport bodies back to St. Petersburg.

The first repatriations of Russian victims could take place Sunday evening, according to Alexei Anikin, head of the Emergency Situations Ministry in St. Petersburg.

Investigators from France and Germany also were expected to join the efforts.

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.

Meanwhile, the plane's black box was transported to Cairo for examination. Egyptian officials have said that initial indications suggested a technical problem downed the plane, but that it was too soon to say what caused the crash.

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.