Pilots first heard about a Chinese live-fire naval exercise near Australia last week when already in the air, receiving messages that forced some to change paths through a busy air corridor, satellite text messages to and from pilots seen by Reuters show.

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.

A series of unexpected live-fire drills by Chinese naval vessels in the Tasman Sea has sparked criticism from Australia and New Zealand and raised questions over regional security. The exercises were conducted by a trio of warships in the international waters beneath a busy commercial flight path,

New Zealand raised fresh concerns Monday over nearby live-fire drills conducted by Chinese warships armed with “extremely capable” weapons, an unprecedented show of firepower last week that analysts say are part of Beijing’s ongoing plan to build a blue-water navy with global reach.