Apparently, although the Tu-204 jet has a capacity of just over 200 passengers, this flight had only eight crewmembers aboard at the time of the crash. Four of the crew died more or less instantly; another died of severe head trauma in the hospital; three were hospitalized with serious injuries but are expected to survive.

I'm not sure if the exact cause is known yet, but to all evidence, the plane was intact until it hit the wall by the highway. In other words, the plane touched down safely (after arriving from the Czech Republic), but failed to stop after landing and was still moving at high speed when it went off the end of the runway.

Whether the cause was ice on the runway or a mechanical failure in the plane itself remains unclear -- but the Russian aviation administration has now voiced some concerns about the reliability of the "thrust reverse" system (which essentially helps the plane to brake after a landing) on this model of aircraft.