China to patrol disputed Diaoyu Islands BEIJING, Dec. 27 (UPI) -- Chinese defense officials said they will step up maritime patrols surrounding a set of islands at the center of a territorial dispute with Japan. Japanese F-15 fighter planes intercepted a Chinese surveillance aircraft headed for the Diaoyu Islands in the East China Sea Saturday. In response, China's Defense Ministry said it will be "highly vigilant" and "protect the country's territorial integrity and maritime rights," Xinhua news agency reported Thursday. Military spokesman Yang Yujun said China's navy will protect the islands, of which both nations claim ownership. "We will decisively fulfill our tasks and missions while coordinating with relevant departments ... so as to safeguard China's maritime law enforcement activities and protect the country's territorial integrity and maritime rights," Yang said. The spokesman criticized Japan for straining relations between the two countries. "China-Japan defense relations are an important and sensitive part of bilateral ties, and the Japanese side should face up to the difficulties and problems that currently exist," Yang said.