TOKYO - Chinese ships sailed through disputed waters off Tokyo-controlled islands on Sunday as diplomatic tension between Tokyo and Beijing intensifies.
Three Chinese coastguard vessels entered the 12-nautical-mile territorial waters off one of the Senkakus, which China claims and calls the Diaoyus, at about 10:00 am (0100 GMT), Japan's coastguard said.
It came days after a diplomatic battle over Japanese Prime Minister Shinzo Abe's visit to a contested war shrine reached the UN Security Council, with China and Japan accusing each other of threatening stability.
China's UN ambassador, Liu Jieyi, seized upon a debate on the lessons of conflict to slam Abe for going to the Yasukuni Shrine, which honours war criminals among the country's war dead.
Last week also saw a report in Japan's Asahi Shimbun newspaper that Chinese air force officials had drafted proposals for a new Air Defence Identification Zone (ADIZ) over the South China Sea.
The United States has warned China that any move to declare a new air zone including disputed islands would be seen "as a provocative and unilateral act that would raise tensions and call into serious question China's commitment to diplomatically manage territorial disputes," State Department deputy spokeswoman Marie Harf told reporters.
She stressed, however, that the reports were "unconfirmed" at this time.
Beijing claims the South China Sea almost in its entirety, even areas far from its shoreline.
In November China abruptly declared an ADIZ over the East China Sea, including the disputed islands at the heart of the sovereignty row with Tokyo, sparking international criticism.
Chinese state-owned ships and aircraft have regularly approached the Senkakus to demonstrate Beijing's territorial claims, particularly after Japan nationalised some of the islands in September 2012.