The Russian passenger jet that crashed in Egypt killing all 224 people on board came down due to "external" factors, the airline says, as relatives began identifying their loved ones in Saint Petersburg.
Senior Kogalymavia executive Alexander Smirnov on Monday said that "no technical failures" could account for why the Airbus 321 would have broken up in mid-air, as investigators have said happened.
"The only explanation is some kind of external action," Smirnov told a news conference in Moscow, without elaborating, adding that the doomed jet was in "excellent technical condition".
Both Cairo and Moscow have played down the claim from Egypt's Islamic State (IS) branch that it brought down the aircraft flown by Kogalymavia between holiday destination Sharm el-Sheikh and Russia's second largest city on Saturday.
The US Director of National Intelligence James Clapper said on Monday he could not rule out IS involvement, but thought it "unlikely".
"We don't have any direct evidence of any terrorist involvement yet," he said.
Investigators are examining all possible causes as they comb the remote crash site in the Sinai peninsula as part of an Egyptian-led probe into the disaster that also involves experts from Russia, Airbus, and Ireland, where the aircraft was registered.
President Vladimir Putin described the crash, Russia's worst air disaster, as a "huge tragedy" in his first comments since Saturday's catastrophe, at a meeting with his transport minister on Monday.
The head of Russia's aviation authority Alexander Neradko slammed the airline's claims that external factors were to blame as "premature and not based on any real facts" in televised comments.
Kremlin spokesman Dmitry Peskov said Moscow "cannot exclude any version" of what caused the crash as investigations were still ongoing, but warned against "guessing" at the reason.
Russia has a dismal air safety record, and while larger carriers have begun upgrading ageing fleets, the crash is likely to raise concerns about smaller airlines such as Kogalymavia.
The company's executive Smirnov said the firm had ruled out a technical fault or human error and said the plane had sustained "significant damage to its construction that did not allow it to continue the flight."
"The crew totally lost control and for that reason there was not one attempt to get in contact and report on the accident situation on board," Smirnov said.
The plane was "flying out of control - that is, it wasn't flying, it was falling," he said.
The claims by the airline came as relatives of those who died in the crash began the painful process of identifying their loved ones after a first plane delivered the remains of 140 victims to Saint Petersburg.
Egyptian authorities said that investigators from the Egypt-led probe team are currently examining the "black box" on-board recorders from the doomed jet in Cairo.
Analysts have dismissed claims the jet could have been shot down by IS-affiliated groups in the region if it was flying at its cruising height of 30,000 feet (9000 metres), but did not rule out that a bomb might have been planted on board.