Japan scrambled fighter planes 156 times in response to Chinese aircraft approaching Japanese airspace in fiscal 2011, a record high number for China since the Defense Ministry started releasing such data by country in 2001, the ministry said Wednesday.

Air Self-Defense Force fighters were scrambled 425 times as a precaution against approaching foreign aircraft in the year to March 31, surpassing 400 for the first time in 20 years, evidence in part of China's increasing military activity, the ministry's Joint Staff said.

By country, the greatest number of operations were against Russian airplanes, at 247 scrambles, down 17 from fiscal 2010.

Chinese planes flew over the East China Sea around the Nansei Islands, including Okinawa, a ministry official said. "Flight patterns have diversified with intelligence-gathering aircraft standing out."