Three Chinese coast guard ships were seen sailing Sunday around the Senkaku Islands in the East China Sea just outside Japan's territorial waters, the Japan Coast Guard said.
Chinese government vessels were last seen around the isles on Feb. 2. The Japan-controlled islets are claimed by China and Taiwan.
The Japan Coast Guard warned the three Chinese ships not to intrude into Japanese territorial waters, and one, responding both in Japanese and Chinese, repeated that the islets are the "inherent territory of China," the 11th Regional Coast Guard Headquarters in Naha, Okinawa Prefecture said.