China's coast guard entered the waters around disputed East China Sea islets on Wednesday to counter what it called the incursion of Japanese vessels into Chinese territorial waters.
Disputed East China Sea islets claimed by China and Japan have long been a sticking point in bilateral ties. China calls the islands Diaoyu while Japan calls them Senkaku.
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 alsois 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.
Wednesday's patrol comes a day before Japanese Prime Minister Fumio Kishida is set to 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 neighbors can form a more united front against Beijing.