A Chinese destroyer conducted live-fire military drills inside Japan’s exclusive economic zone (EEZ) near Okinotorishima island over the weekend, Defense Minister Shinjiro Koizumi announced, as Russian warships observed — the latest signal of Beijing and Moscow’s growing defense ties.

The announcement was the first time Tokyo had spotted and made public a live-fire drill by the Chinese military within Japan’s EEZ.

“At this moment, Chinese and Russian naval vessels are conducting joint navigation operations in the waters surrounding Japan,” Koizumi said in a speech at the Farnborough International Airshow in Farnborough, England, on Monday.