The number of times Japanese air force planes scrambled to intercept Chinese planes more than doubled year-on-year. Flights to intercept Russian planes rose even more. Japan's Defence Ministry said Air Self-Defence Force jets were scrambled 96 times in the year to March 31 to ward off Chinese planes, the Yomiuri Shimbum reported. Japan said no foreign aircraft violated Japanese airspace during the 12-month period but Chinese military planes had come close to Japanese airspace over the Diaoyu Islands for the first time on March 2. Japanese jets were scrambled after Chinese aircraft were spotted flying over the East China Sea towards the Ryukyu Islands and approaching an area about 50 kilometres from Japanese airspace, it said. Chinese planes accounted for only 25 per cent of such foreign aircraft 'interceptions'. Russian aircraft were warded off on 264 occasions, an increase of 30 per cent, and accounted for 68 per cent of such flights, the Yomiuri Shimbum reported. Meanwhile, China's State Oceanic Administration said it strengthened its marine enforcement operations last year, including actions to safeguard China's maritime rights. In its annual report, the SOA said 228 vessels from an unnamed foreign country were warned off in the South China Sea, and warnings were given to 40 other merchant and fishing vessels. During Sino-US talks in Beijing last month, China asked that American vessels and planes stop surveillance operations in Chinese economic zones. The report also said the SOA had launched operations to safeguard an oil and gas field in the East China Sea, where Japan and China are in dispute over rights to drill for oil and gas.