ATHENS (Reuters) -A Ukrainian cargo plane carrying munitions from Serbia to Bangladesh crashed in northern Greece late on Saturday, killing all eight crew members on board, Greek and Serbian authorities said on Sunday. Witnesses said the aircraft had come down in a ball of flames near the city of Kavala before exploding on impact in corn fields around midnight local time. Earlier the pilot had reported engine trouble and had requested an emergency landing. Drone images from the scene showed smouldering debris from the Antonov An-12 aircraft strewn across fields. Ukrainian-based airline Meridia…