the civil war going on on the eastern ukraine border, to paraphrase the russian play write anton chekovif you bring a gun on stage, it's going to go off. right now, russian leader vladimir putin has pulled a whole lot of firepower on the border, 17 battalions, some 20,000 troops ready for action as this is dangerous human drama continues to play out on the world stage. meanwhile, pro-russian rebels inside ukraine have reportedly shot down another ukrainian military jet with a russian made surface-to-air missile system according to kiev. our senior international correspondent nick paton walsh is risking life and live to bring us the latest from this war zone. tell us about the latest shootdown and the russian threat on the border. >> reporter: well, the reason why many have focused on this latest shootdown mig 29 near a north to the crash site of mh-17 is because ukrainian officials claim it was taken down by a bottom missile system, the same one they claim as u.s. officials do, as well that took out mh-17. this is happening as the ukrainian military is advancing fast towards where i in