Japan scrambled fighter jets in response to Chinese aircraft a record number of times in the year to March 2013, mostly after the nationalisation of disputed islands, the government said Wednesday.
Jets were sent airborne 306 times over the 12 months, double the previous year and more than the number of times they reacted to Russian planes -- 247 -- for the first time on record, the Defence Ministry said in a press release.
In September last year, the Japanese government bought three of the five Senkaku islands in the East China Sea, known and claimed as the Diaoyus in China.
More than three-quarters of the mobilisations against Chinese aircraft, a total of 237, were in the October to March period.
On December 13, a Y-12 turbo-prop plane from China's State Oceanic Administration breached airspace over the disputed islands, prompting the launch of Japanese F-15s.
It was the first known incursion ever by a Chinese plane into Japanese airspace, the government said at the time.
State-owned Chinese ships have sailed close to the disputed islands dozens of times since September, sometimes moving into 12-nautical-mile territorial waters around them.
In recent years Russian fighter patrols near islands that Moscow and Tokyo both claim have been the most common cause of Japanese airborne responses.