Three Chinese patrol ships have sailed into the territorial waters off the Senkaku Islands in the East China Sea. The Japan Coast Guard is demanding the Chinese government vessels leave the Japanese waters. A Coast Guard patrol ship spotted the Chinese marine surveillance vessels about 22 kilometers southeast of one of the Senkaku Islands on Monday morning, according to Japan’s (NHK WORLD) website. The islands are controlled by Japan but claimed by China and Taiwan. Japan’s foreign ministry lodged a protest to China over the incursion, saying the Senkakus are Japan’s inherent territory. But China rejected the protest, insisting that it has sovereignty over the islands. China has had an almost constant patrol ship presence in Senkaku waters since Japan nationalized the disputed islands last September. Chinese patrol ships also intruded into the area on Saturday.