Australia learned about Chinese live-fire naval drills off the country’s coast that forced dozens of flights to be diverted via an alert from a commercial pilot, authorities said on Monday.

Commercial airliners flying over the Tasman Sea between Australia and New Zealand were forced to reroute their flights on Friday morning Australian time because of a People’s Liberation Army Navy (PLAN) action group warning that it would conduct live-fire drills.

Australia warned international airlines flying between Australian airports and New Zealand to beware of Chinese warships conducting a live-fire exercise in the Tasman Sea, Foreign Minister Penny Wong said Friday.