The European air traffic control body, Eurocontrol, said Ukrainian authorities had banned aircraft from flying at 32,000ft or below and the doomed aircraft had been cruising above that, at 33,000ft – however this apparently still left it within range of the sophisticated surface-to-air weaponry that pro-Russia forces have been using recently to target Ukrainian military aircraft. All civilian flights have now been barred from the area of eastern Ukraine.
http://www.theguardian.com/world/2014/jul/18/mh17-pressure-o...