The Royal Australian Air Force (RAAF), monitoring a Chinese navy warship as it circumnavigated Australia last month, heard it warn it would use live fire in its exercises on a civilian radio broadcast, defence pilots said on Tuesday. A People's Liberation Army Navy frigate conducted the unprecedented live-fire exercise in the Tasman Sea between Australia and New Zealand in February, causing 49 commercial flights to be rerouted. China has said it gave adequate warning about the drill under international law, but Australian and New Zealand authorities said it fell short of best practice for notifications.