the german government had been warned of a heightened from the day before when a ukrainian air force plane was shot down at around 20,000 feet over rebel-held .
malaysia airlines flight mh17 was shot down over rebel-held territory in eastern ukraine on july 17 , and all 298 aboard were killed .
warning : despite being told of the risk of flying over ukraine in diplomatic cables sent two days before the crash , germany failed to pass on the warning , local media reported .