South China Morning Post 
January 11, 2013
Japan’s defence ministry is considering authorising the country’s Air Self-Defence Force (ASDF) jets to fire warning shots when Chinese planes enter air space claimed by Japan, Japanese media reported yesterday.
Citing sources close to the Japanese government, the Sankei newspaper reported that Tokyo had instructed the defence ministry and ASDF to look at stepping up warnings to People’s Liberation Army planes and Chinese government aircraft that “intrude into Japanese air space”.
In Beijing, the foreign ministry said China opposed any infringement of its sovereignty over the Diaoyu Islands committed by Japanese aircraft or vessels and remained vigilant against attempts to commit such acts.
“Diaoyu Island and its affiliated islets have been China’s inherent territory. Patrols conducted by Chinese planes and ships in waters off the islands represent normal administrative activities for the purpose of exercising jurisdiction,” ministry spokesman Hong Lei said in response to a question about the Japanese report.
The report said the number of Chinese military planes flying near Japan’s “air-defence identification zone”, including the PLA Air Force’s Y-8 multi-role cargo planes and other intelligence-gathering aircraft, had increased since Japan bought three of the disputed islands, in the East China Sea, in September.