China disputes Japan's territorial claims over disputed waters in East China Sea

China's foreign ministry on Thursday countered Japan's territorial claims over disputed waters in the East China Sea, calling the move a "grave violation" of Chinese sovereignty.

"Chinese coast guard vessels carried out law enforcement on the scene in accordance with the law, it is a legitimate measure to safeguard Chinese sovereignty," spokesperson Wang Wenbin told reporters at a regular press briefing.

Wang made the remarks in response to a question on Japan's coast guard saying Chinese coast guard vessels violated Japanese territorial waters around the disputed East China Sea islets.

The area is claimed by both China and Japan and has long been a sticking point in bilateral ties. China calls the islands Diaoyu while Japan calls them Senkaku.

China's coast guard said on Wednesday it entered the waters around disputed East China Sea islets to counter what it called the incursion of Japanese vessels into Chinese territorial waters.

China Marine Police spokesperson Gan Yu said in a statement that coast guard vessels entered the waters of the Diaoyu for a "normal rights protection patrol" calling it a "routine move".

"(This also）is a strong countermeasure to the Japanese side's intrusion of one yacht and several patrol vessels into our territorial waters," Gan said, though he did not specify any incident.

China's coast guard said in late January that the Shinsei Maru and four other Japanese ships illegally entered the territorial waters of the Diaoyu islands before being driven away by Chinese coast guard vessels.

On Thursday, Japanese Prime Minister Fumio Kishida will hold a summit with South Korean President Yoon Suk Yeol in Tokyo, the first such meeting in Japan in more than a decade, at a time when the United States hopes the two neighbours can form a more united front against Beijing.