China has deployed both of its aircraft carriers—CNS Liaoning and CNS Shandong —to the east of the first island chain since June 7. Japan's military reported that its patrol aircraft was intercepted by fighter jets launched from the Shandong while conducting surveillance.

Beijing condemned on Thursday what it called "dangerous behaviour" by a Japanese military plane over the Pacific after Tokyo said Chinese fighter jets flew unusually close to its aircraft at the weekend.

Two of Beijing's aircraft carriers were sighted simultaneously in the Pacific for the first time on Saturday and Sunday.