(NEWSER) – If ISIS really did bring down a Russian passenger jet in Egypt, it wasn't with a missile, according to American officials. US officials tell CNN and NBC News that an American infrared satellite detected a heat flash in the area at the time of the crash, but not the heat trail of a missile.

Analysts say the heat flash could have been caused by a number of things, including a bomb, a fire on the plane, a fuel tank exploding, or even the plane slamming into the ground, although an official tells NBC it appears that the plane "disintegrated at a very high altitude," as Russian authorities have said. The airline says it has determined that "external activity" is the only thing that could have caused the crash of Flight 9268.

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