The Chinese Defense Ministry on Saturday issued a map of an East China Sea Air Defense Identification Zone that includes a chain of disputed islands also claimed by Japan, triggering a protest from Tokyo.
Beijing also issued a set of rules for the zone, saying all aircraft must notify Chinese authorities and are subject to emergency military measures if they do not identify themselves or obey orders from Beijing. It said it would "identify, monitor, control and react" to any air threats or unidentified flying objects coming from the sea.
The rules went into effect Saturday.
In Tokyo, Junichi Ihara, head of the Foreign Ministry's Asian and Oceanian Affairs Bureau, protested by phone to China's acting ambassador to Japan, Han Zhiqiang, saying the zone is "totally unacceptable," according to a ministry statement.
Ihara also criticized China for "one-sidedly" setting up the zone and escalating bilateral tensions over the islands.
Both Beijing and Tokyo claim the islets, called Diaoyu in Chinese and Senkaku in Japanese. Protests erupted throughout China last year to denounce the Japanese government's purchase of the islands from private ownership.
A rising economic and military power, China has become more assertive over its maritime claims. It has been in disputes with several neighboring countries over islands in the East and South China seas.
"By establishing the air-defense zone Beijing has ... potentially escalated the danger of accidental collisions between the Chinese military and the U.S. and Japanese counterparts," said Tomohiko Taniguchi, a counselor in the office of Japanese Prime Minister Shinzo Abe. "It poses a serious challenge against freedom of movement in the sky and in the seas."
China said the zone is in line with the practice of other nations that have similar zones to protect their coasts. The new zone overlaps with Japan's existing zone, which also includes the disputed islands.
"This is a necessary measure taken by China in exercising its self-defense right," Chinese Defense Ministry spokesman Yang Yujun was quoted as saying on the ministry's website. "It is not directed against any specific country or target. It does not affect the freedom of over-flight in the related airspace."
South Korea and Taiwan also claim the barren, uninhabited islands in the East China Sea.
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