Russian media reports have said the terrorist bomb that downed an airliner in Egypt at the end of October was probably brought on board by personnel at Sharm el-Sheikh airport and set off by a timer.

On Tuesday, the Kremlin confirmed that a bomb had destroyed the plane and vowed to hunt down those responsible. Before then it had been reluctant to admit the likelihood of a terrorist attack against the St Petersburg-bound Airbus A321 that crashed, killing all 224 people on board.

An Isis-affiliated group claimed credit for downing the plane in a statement on the day of the crash but did not describe its methods. The Isis online magazine, Dabiq, published on Wednesday what it claimed was an exclusive photograph of the improvised bomb, made from a Schweppes drink can, though airline security experts questioned how it would have been detonated without an Isis operative on the plane.

The Russian newspaper Kommersant reported on Wednesday that investigators from the FSB intelligence agency had discovered a one-metre hole in a fragment of the plane’s fuselage with its edges turned out, indicating an explosion.



It quoted a source close to the investigation saying the blast had occurred in the rear of the passenger cabin, near the frame of the tail. The bomb was probably placed under a window seat, the source said. Its detonation caused an explosive loss of cabin pressure, detachment of the tail and the breakup of the plane in mid-air. Those on board died almost instantly from the sharp drop in pressure, the newspaper reported.

Egypt plane crash: Russia says jet was bombed in terror attack Read more

The bomb is likely to have been brought on board by airport service personnel, such as cabin cleaners or workers delivering baggage and food, and set off by a timer, though another possibility is that it went off when a sensor detected falling pressure as the plane gained altitude, Kommersant reported.

The Interfax news agency quoted a source who said the device had been made from a “substance used in military shells and bombs”, probably plastic explosives, and set off by a timer. The source said the attackers must have known about frequent delays in tour operator flights from Sharm el-Sheikh and that airport employees had probably placed the bomb on board after the final flight time was determined.

The online tabloid LifeNews published backdated footage on Tuesday of Russian emergencies ministry workers discovering a badly burnt suitcase at the crash site, which it speculated could have held the bomb.

Experts expressed scepticism that the device in the Dabiq picture could have been behind the crash. Norman Shanks, a former head of security for BAA and Heathrow, said that an improvised device would probably have to be significantly larger to create the explosive blast of 1kg of TNT, the equivalent force that Russian officials said brought down the plane.

He also said the purported bomb appeared to have no timer or barometric device to trigger an explosion at altitude, and so would need to be manually activated. “It could have been put on the aircraft before the flight by airport staff but would have to be triggered by someone in the cabin, which means a passenger or crew member,” he said.

“I imagine that the Russians are now looking again at the passenger and crew manifest to see if there are any connections, but I personally have doubts. It wouldn’t surprise me if this was being put out to cover up how they got the actual device in.”

As well as publishing a picture of the purported bomb, Dabiq claimed that bombers had made advanced plans but chose to target a Russian airliner, instead of another country’s planes, only after the Russian president, Vladimir Putin, launched airstrikes. Its edition claims: “And so after having discovered a way to compromise the security at the Sharm el-Sheikh international airport and resolving to bring down a plane belonging to a nation in the American-led western coalition against the Islamic State, the target was changed to a Russian plane.”

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The FSB head, Alexander Bortnikov, informed Putin during a televised briefing on Monday night that the plane crash was “unequivocally a terrorist act” caused by an explosive device. Putin declared Russia would find those guilty “anywhere on the planet and punish them”. He also ordered Russia’s military to intensify its airstrikes in Syria.

On Wednesday, the Russian foreign minister, Sergei Lavrov, said Moscow had already received some responses to its request to other governments for intelligence that could lead to those responsible being identified, calling the bombing “equivalent to an attack on the state”.

Lev Gudkov, director of the independent pollster Levada Centre, said that rather than calling into doubt Putin’s intervention in the Middle East, news that a terrorist attack brought down the plane would probably strengthen the “opinion that propaganda is pushing on people – that the Russian position on Syria is necessary”.