(VOVworld) - The Japanese Coast guard reported 3 Chinese marine surveillance ships on Sunday sailing through disputed waters off islands in the East China Sea, known as Senkaku in Japan and Diaoyu in China. 

The islands known as Diaoyu in Chinese and Senkaku in Japanese have been claimed by both countries (Photo: Reuters)

This is the first time that Chinese Coast Guard ships were spotted sailing through the waters since Beijing raised regional tensions with its announcement of an Air Defence Identification Zone. China’s air zone mostly overlaps existing zones of China, South Korea, and the disputed islands.

Chinese state-owned ships and aircraft have approached the area on and off to demonstrate Beijing’s territorial claims, especially after Japan nationalized 3 of the 5 islands last September.