That didn't take long: following the worst Russian airplane disaster in history, the question everyone was asking is who is responsible. Moments ago we may have gotten the answer.

A militant group affiliated to Islamic State in Egypt claimed responsibility for the downing of a Russian passenger plane that crashed in Egypt's Sinai peninsula on Saturday, the group said in a statement circulated by supporters on Twitter.

Below is the full statement from a group alleging to speak on behalf of Islamic State, posted on their affiliate site, translated by the Guardian's Jahd Khalil. It offers no evidence that the group brought down the plane, apart from their word.

Breaking: Downing of Russian airplane, killing of more than 220 Russian crusaders on board. Soldiers of the Caliphate were able to bring down a Russian plane above Sinai Province with at least 220 Russian crusaders aboard. They were all killed, praise be to God. O Russians, you and your allies take note that you are not safe in Muslims lands or their skies. The killing of dozens daily in Syria with bombs from your planes will bring woe to you. Just as you are killing others, you too will be killed, God willing.

The tweet in question:

Many expressed their initial skepticism that ISIS is the responsible party:

UPDATE: Responding to IS claim, Russian Transport Ministry says it "can't be considered true;" plane at 31k feet, outside MANPAD range, @BBC — Stratfor (@Stratfor) October 31, 2015

#ISIS claim re. #Russia airliner -- 3 possibilities: 1. False claim 2. Bomb on plane 3. ISIS [somehow] has advanced air defense missiles. — Charles Lister (@Charles_Lister) October 31, 2015

An analyst with the Center for American Progress, Mokhtar Awad, told the Guardian that the Islamic State’s claim of responsibility "is quite vague.

“It doesn’t state how they were able to ‘down’ the plane allegedly. Even the most sophisticated of portable surface-to-air missiles cannot reach that high an altitude and are only a threat during periods of take-off or landing, but the plane had already climbed to its target altitude (from what we know thus far) when it began to likely experience technical failures. The local affiliate, Wilayat Sinai, has been under some pressure over the past few months and may have jumped the gun on taking credit. Although there isn’t a precedent for such a spectacular lie about something they claim to have done, Islamic State itself has recently been embellishing more and more. For instance it claimed that the recent prison raid by Kurdish and US special forces were a total failure, when in fact video evidence surfaced showed them freeing the hostages. So this may be an instance of the rooster taking credit for the dawn.”

Of course, it could simply have been a bomb planted on the plane and set to explade after 20 minutes of flight time.

Another theory that has emerged is that a prior structural shock (in 2001) led to a spontenous midair disintegration:

What jumps out from this particular airplane’s record is an accident that it suffered on November 16, 2001 while landing at Cairo (while owned and operated by Middle East Airlines). As it touched down the nose was pointing at too high an angle and the tail hit the tarmac – heavily enough to cause substantial damage. Tail strikes like this are not uncommon. The airplane was repaired and would have been rigorously inspected then and during subsequent maintenance checks. Nonetheless investigators who will soon have access to the Airbus’s flight data recorder will take a hard look at what is called the rear pressure bulkhead, a critical seal in the cabin’s pressurization system. Images from the wreckage in the Sinai show parts of the tail and rear fuselage near the site of this bulkhead lying clear of the rest of the debris, suggesting a possible break-up in flight. In the event of a failure of this bulkhead, the airplane would have suffered a sudden and potentially explosive decompression; at its final recorded altitude of 31,000 feet the difference between the pressure inside the cabin and the air outside would have been at the point where such a catastrophic failure would be most likely to occur. The wreckage shows no signs of a fire or an engine-related explosion.

On the other hand, this is like saying Lehman had an earnings miss in 1994 and filed bankruptcy 14 years later.

Even Russia's transport minister Maksim Sokolov has said that the claim Islamic State militants brought down the plane "can’t be considered accurate".

Now in various media there is assorted information that the Russian [plane]... was supposedly shot down by an anti-aircraft missile, fired by terrorists. This information can’t be considered accurate.

However, to corroborate their claim, ISIS has allegedly released this shocking video showing what appears to be a mid-air bomb explosion.

Viewer discretion advised.

Although according to latest social media updates, even IS Sinai is stating that this video is fake.

IS Sinai says purported vid of Russian plane being down is a fake — Samer Al-Atrush (@SameralAtrush) October 31, 2015

As a reminder, this is where the alleged explosion occurred:

Whether or not the video is real or staged like many of ISIS' previous "made in Hollywood" productions, is currently unknown.

Of course, is the same ISIS which a recently leaked CIA report revealed as being created by the CIA as a "tool" to overthrow Syria's Assad.

In other words, a proxy organization of US "shadow government destabilizing operations", trained in U.S. ally Turkey, and openly funded by both U.S. allies Saudi Arabia and Qatar, just took down a Russian plane.

The question now is did ISIS use a US-made surface-to-air missile to start what may be a very unpleasant war.



Also, does Russia get a carte blanche to begin attacks on ISIS in Egypt now, the same Egypt which recently "purchased" the two Mistral ships made by France, which were meant to be bought by Russia in a deal that was scrapped in the last minute due to NATO intervention?

One thing is clear: if the Russian population had any qualms about continuing the campaign in Syria, they were just eliminated in perpetuity.

We now await the Russian response, against both ISIS and its direct and indirect sponsors.