BEIJING (Reuters) - A number of Chinese fishermen are missing after a trawler sank on Friday in waters to the north of islands disputed with Japan in the East China Sea, state media said, though it was unclear what had caused the sinking in highly sensitive waters.
The boat sank in the morning north of the islands which China calls the Diaoyus and Japan the Senkakus, the official Xinhua news agency said, citing naval sources.
The dispute over the Japanese-held islets, where Chinese and Japanese ships regularly engage in a cat-and-mouse game, has raised fears of a clash between Asia's biggest powers that could even drag in the United States.
"The cause of the accident is yet to be known. Two Chinese naval rescue vessels are heading to the scene," Xinhua said in a brief dispatch.
Japan's Coast Guard said it had sent an aircraft and a patrol boat to the area, about 120 km (75 miles) to the north of the uninhabited islands, which it said were in international waters.
The state-run Beijing Times said on its microblog that the trawler had taken on water and sunk. Two Chinese naval ships nearby came to the scene and rescued five of the sailors while another five were missing, it added.
China's proclamation last November of an air defence zone covering large parts of the East China Sea has raised concerns that a minor incident could quickly escalate.
China also claims almost the entire South China Sea, rejecting rival claims to parts from Vietnam, the Philippines, Taiwan, Malaysia and Brunei in one of Asia's most intractable disputes and another possible flashpoint.
(Reporting by Ben Blanchard; Additional reporting by Kiyoshi Takenaka in TOKYO; Editing by Nick Macfie)