territory that you mentioned, you have to know, they were placing their shooting systems and firing those missiles themselves. everybody must know that if we are pressing a corner, on our territory, we will respond the way we can. >> nbc's richard engel is in ukraine with more on that strike. >> russian officials say ukraine took the war to russia, launching a cross border attack with to combat helicopters. this video appears to show their tracer rounds destroying a fuel depot, 20 miles from the ukrainian border. a senior u.s. defense official tells nbc news that ukraine was responsible for the daring raid, ukraine's first of the war. ukraine's official response seemed deliberately ambiguous, with defensive issues saying they couldn't confirm or deny