Witnesses saw an explosion on board a Russian passenger plane just before it crashed late on Tuesday near the town of Tula, Interfax news ...
It looks like they took off around the same time and they went down about the same time. Sounds to me more like a timed explosion, rather than ground to air. I don't believe this is an accident as most accidents occur shortly after takeoff or shortly before landing. These were apparently in mid-flight. Hmmm.