Something appears to have gone seriously wrong with a drone mission in Ukraine after an unmanned military aircraft crashed hundreds of miles away from the war zone in the capital of Croatia. According to the Associated Press, witnesses in Zagreb told reporters that they heard a massive explosion on Thursday night followed by a terrible smell. Police who responded to the scene found a big crater full of twisted metal and a parachute that got caught in a tree branch, according to the AP report. Croatia’s National Security Council confirmed Thursday that a “pilotless military aircraft” entered Croatian airspace from neighboring Hungary, which shares an eastern border with Ukraine. If it is from the war zone, it must have flown at least 350 miles and was undetected by at least two NATO members. The War Zone online magazine reported the drone is likely to be a Soviet-era Tu-141 “Strizh” craft operated by Ukraine’s military. Ukraine’s defense ministry said Friday that the drone was not one of theirs.