CHINA and Japan summoned each other's ambassadors for a verbal dressing down as the war of words over Beijing's new air defence zone grew more heated, and Prime Minister Shinzo Abe weighed in for the first time.
The Chinese ambassador to Tokyo got an earful from Japanese officials over China's Air Defence Identification Zone (ADIZ) covering the East China Sea, which includes a small island chain that Beijing claims as Diaoyu and Tokyo claims as Senkaku.
Beijing called in the Japanese envoy to lodge its "strong dissatisfaction and solemn protest over Japan's unreasonable hype".
Mr Abe, speaking in Parliament yesterday, expressed strong concerns over "a profoundly dangerous act that may cause unintended consequences".
"Japan will ask China to restrain itself while we continue cooperating with the international community," he said in his first remarks since China announced the setting up of the ADIZ on Saturday morning.
The zone, which overlaps Japan's by almost half, has raised fears of possible armed conflict in one of the world's most volatile regions. Naval vessels and aircraft from both sides have engaged in numerous cat-and-mouse tussles since Tokyo nationalised three of the isles in September last year, sparking street protests and a boycott of Japanese goods in China.
Chinese media and analysts defend the ADIZ as a move well within China's right, pointing to how more than 20 countries, including the United States and Japan, have had such zones for decades.
ADIZs are pre-defined areas - usually outside a country's territorial airspace - set up for early detection and monitoring of aircraft for security purposes.
China says aircraft flying in the zone will have to obey its self- identification rules or face "defensive emergency response", which is taken to mean possible military action, say analysts.
Singapore-based defence expert Richard Bitzinger said: "China's move could be seen as a deliberately provocative act that could increase the probability of conflict in and around the zone."
Various regional airlines say they will submit flight plans to the Chinese authorities, but diplomats worry that doing so would be seen as a tacit acknowledgement of China's sovereignty claims.
China's ADIZ also overlaps part of South Korea's zone, including a rock known as Ieodo that remains a bone of contention with Beijing.
"I would like to say once again that we have unchanging territorial control over Ieodo," South Korean Defence Ministry spokesman Kim Min Seok said yesterday.
Chinese Foreign Ministry spokesman Qin Gang told a regular press briefing that China and South Korea are friendly neighbours and have no territorial disputes. "The two sides will resolve the issue of maritime boundary demarcation through friendly consultations and negotiations."
He also urged the US not to take sides and to stop making irresponsible comments.
Washington, which expressed deep concern over the zone, has pledged to stand by Japan in the event of a clash with China.
Chinese state media continued to slam Japan, with the Global Times calling Tokyo "impudent" and "hypocritical" because its own zone is as close as 50km from Russia and 130km from China.
"If Japan sends warplanes to 'intercept' China's jet fighters, Beijing's armed forces will be bound to adopt defensive emergency measures," it said.