Three China Coast Guard ships sailing near the Diaoyu Islands in the East China Sea, known to Japan as the Senkaku Islands, were in Japanese territorial waters for about two hours on Tuesday, the Japan Coast Guard said. China Coast Guard ships last entered Japanese territorial waters on December 23. Chinese government ships have been spotted in Japanese waters a total of 32 days since the beginning of this year. A Japanese coast guard patrol ship issued a warning urging the ships, identified as the Haijing 2102, 2166 and 2401, to leave the waters. One of them responded that the islands are ”inherent territory of China,” according to the 11th Regional Coast Guard Headquarters in Naha, Okinawa Prefecture. China and Japan both claim sovereignty over the uninhabited islands, which are administered by Japan. Chinese ships have repeatedly entered the waters around them in recent years, raising tensions between the two countries.