TOKYO, Oct. 25 (UPI) -- The Japanese government filed a protest with China Monday, complaining about the alleged presence of Chinese patrol boats near disputed islands.
Japanese naval authorities reported sighting two Chinese patrol boats late Sunday near disputed islands, CNN reported.
A protest document criticizing China was sent to the Chinese Embassy in Tokyo last week for the second time in October, Kyodo News reported. Police said the document expressed disapproval of China's handling of developments over collisions between a Chinese trawler and two Japanese patrol boats.
Both countries claim sovereign rights to the islands called the Senkaku Islands in Japanese and the Diaoyu Islands in Chinese, CNN reported.
Media reports said the incident Sunday indicated the Chinese boats were in Japan's "contiguous zone" but didn't cross into Japanese territorial waters. However, the protest to China said the presence of Chinese patrol boats made the Japanese government feel "uncomfortable."
China's foreign ministry has said the boat patrols are both legal and based on need.
Japanese Chief Cabinet Secretary Yoshito Sengoku said Japan will increase its monitoring around the islands and add six submarines to its 16-vessel fleet during the next four years.