China's defense ministry has released an air defense zone map for the East China Sea that includes islands controlled by Japan, but claimed by China.
In a statement on its website Saturday, the ministry said that under a new set of rules, all aircraft entering the zone must notify Chinese authorities and are subject to emergency military measures if they do not identify themselves or obey orders from Beijing. The statement said the rules went into effect on Saturday.
There was no immediate response from Japan, but earlier this month, Japan scrambled fighter jets in the East China Sea after it spotted what it said was an unmanned aircraft flying toward Japan.
The islands, known as Senkaku in Japan and Daioyu in China, are uninhabited, but surrounded by rich fishing grounds and potential energy deposits.
Japan annexed the islets in the late 19th century. China claimed sovereignty over the archipelago in 1971, saying ancient maps show it has been Chinese territory for centuries.