U.S. satellite images suggest that an explosion downed a Russian passenger jet over Egypt's Sinai Peninsula on October 31, casting doubt on the theory that the airliner was struck by a missile.
A senior U.S. defense official said on November 2 that infrared images of the area taken when the Airbus A321-200 was in the air detected a heat flash that suggests the plane was destroyed internally by a bomb or a fuel-tank explosion.
"There was an explosion of some kind" and "the plane disintegrated at a very high altitude," the official told U.S. television network NBC. He said there was "no evidence a missile of any kind brought down the plane."
That a missile had struck the plane was among the handful of theories that emerged after Kogalymavia/Metrojet Flight 9268 went down, killing all 224 on board.
A few hours after the crash, an affiliate of the Islamic State (IS) group that is fighting Egyptian forces in the Sinai claimed responsibility for downing the plane in response to Russian air strikes in Syria, although Russian officials have questioned the credibility of the claim.
Experts had expressed doubt that militants in the area possessed missiles capable of hitting an aircraft flying at more than 9,100 meters, although the possibility of a bomb blast or other internal explosion was not ruled out.
Speaking to NBC, the U.S. official said the satellite would have detected the heat trail from a surface-to-air missile aimed at the plane.
The United States, Germany, and Britain all had overflight warnings for Egypt's Sinai Peninsula at the time of the crash.
The warnings, in place until 2016, advise airlines to avoid flying over the peninsula below 8,000 meters (26,000 feet) and note the danger posed by antiaircraft weapons capable of reaching high altitudes. They also caution airlines to avoid the Sharm el-Sheik airport due to extremist violence.
Airline: Plane In 'Excellent Condition'
The deputy general director for the airline company Kogalymavia, which operates as Metrojet, said on November 2 that pilot error or technical problems were not to blame for the crash of the jet in Egypt.
Aleksandr Smirnov said that the crash could only have been the result of some other "technical or physical action."
"The plane was in excellent condition," Smirnov told a news conference in Moscow. "We rule out a technical fault and any mistake by the crew."
The head of Russia's aviation authority, Aleksandr Neradko, criticized the airline's comments, however, saying they were "premature and not based on any real facts."
Kremlin spokesman Dmitry Peskov said that in the investigation Moscow "cannot exclude any version" but warned against "guessing" the cause of the crash.
The Airbus went down over Egypt's Sinai Peninsula on October 31 about 23 minutes after taking off from the Red Sea resort of Sharm el-Sheikh en route to St. Petersburg. Officials say the crash is the deadliest air disaster in Russian and Soviet aviation history.
Reuters, citing an unnamed official on a committee investigating the plane's flight recorders, said the jet was not struck from the outside and the pilot did not make a distress call.
Interfax, citing a source in Cairo familiar with the situation, reported on November 3 that recordings revealed "routine communication" with air-traffic controllers in the minutes leading up to the disaster.
However, the source said that "sounds uncharacteristic of a standard flight" preceded the airliner's disappearance from radar screens, suggesting that something "took the crew by surprise."
The lack of a distress call, and the fact that the wreckage was strewn over a wide area, have helped support the widespread belief that the aircraft broke up suddenly in midair.
However, the spokesman of Egypt's Civilian Aviation Ministry, Mohamed Rahmi, warned against reaching premature conclusions. "This could be a long process and we can't talk about the results as we go along," he told Reuters on November 3.
The Egyptian government has said the black-box recorders are being examined by Egyptian and Russian experts along with specialists from Airbus and from Ireland, where the aircraft was registered.
IS Revenge For Syria?
U.S. officials have said they are not aware of any direct evidence of terrorist involvement.
Asked about the ability of IS militants to bring down an airliner, the director of U.S. national intelligence, James Clapper, told media, "It's unlikely, but I wouldn't rule it out."
Russia's Emergency Situations Ministry has said that 140 bodies and more than 100 body parts were delivered to St. Petersburg on two government planes this week.
A third plane was expected to bring more remains on November 3.
Russian officials announced on November 3 that 10 bodies had been identified by their families.
With reporting by Reuters, AP, AFP, and NBC News