By Nobuhiro Kubo
TOKYO (Reuters) - Japan protested after Chinese fighter jets flew "abnormally close" to Japanese military aircraft over the East China Sea on Wednesday, Defence Minister Itsunori Onodera said.
The newest flare up in a long-running territorial dispute between Asia's largest economies follows a similar incident on May 24, when Japan said Chinese aircraft had come within a few dozen metres of its warplanes.
The Chinese Su-27s "flew so recklessly that the Self-Defense Forces pilot felt in danger," Onodera told visiting Australian Defence Minister David Johnston.
"I would like the Chinese military authorities who allow this kind of dangerous behaviour to take place to behave morally."
China's defence ministry did not immediately respond to a request for comment.
China lays claim to Japanese-administered islets in the East China Sea, known as Senkaku in Japan and Diaoyu in China. It is also pressing its claim to almost all the South China Sea, brushing aside claims by several southeast Asian states.
Japan's Defence Ministry said the Chinese fighters came "abnormally close" to a Japanese OP-3C surveillance plane and a YS-11EB electronic intelligence aircraft between 11 a.m. and 12 a.m.
The ministry's statement did not say how close the planes came to each other but added that neither the planes nor the Japanese pilots suffered damage or injury.
China's proclamation last November of an air defence zone covering disputed islands and areas in the South China Sea has fuelled concerns that a minor incident could quickly escalate.
Sino-Japanese ties have long been strained by allegations in China that Japan has not properly atoned for its wartime aggression and by the spat over the uninhabited islands.
Japan scrambled fighter jets against Chinese planes 415 times in the year ended in March, up 36 percent on the year, while in waters near the disputed islands, patrol ships from both countries have been playing cat-and-mouse, raising fears of an accidental clash.
Japanese land, sea and air forces joined last month to simulate the recapture of a remote island, underscoring Tokyo's concerns about the security of the islets.
Tensions between China and its neighbours have also risen sharply in the South China Sea in recent weeks, following the deployment of a Chinese oil rig in waters also claimed by Vietnam. The deployment sparked anti-Chinese riots in Vietnam.
The Philippine foreign ministry in May accused China of reclaiming land on a disputed reef in the South China Sea and said it appeared to be building an airstrip.
(This story was refiled to delete extraneous word in headline)
(Reporting by Nobuhiro Kubo in Tokyo and Ben Blanchard in Beijing; Writing by Antoni Slodkowski; Editing by William Mallard and Clarence Fernandez)