The Chinese army is weighing the full use of unmanned aircraft to regularly monitor the East China Sea, a move that may add fuel to heightened tension in the area where Japanese-controlled islands claimed by China lie, a Chinese document on the country’s use of drones showed on Friday. The document compiled in October suggested the need for the People’s Liberation Army to use military unmanned aircraft, noting that the current patrolling activities in the East China Sea through Chinese official ships dispatched there is not enough to protect the country’s interests. Chinese vessels are frequently spotted in the sea area claimed by Japan as its territorial waters. They claim Beijing’s sovereignty over the disputed islands. A drone was detected near the Japanese-administered Senkaku Islands, called Diaoyu in China, on September 9, 2013, prompting Japan’s Air Self-Defence Force to scramble fighter jets. Quoting experts on Chinese military drones, the document highlighted the importance of using unmanned aerial vehicles to counter repeated US surveillance activities by its Global Hawk drones in the East China Sea as well as to deal with territorial disputes with Japan. The document also said Beijing has the legal grounds to conduct periodical unmanned aircraft surveillance because China has established an air defence identification zone over the East China Sea in November 2013. The Chinese army owns some 50 military unmanned aerial vehicles, including its Yilong drone that is seen as most suitable for a mission in the East China Sea because it has a range of 4,000 kilometres and can fly 20 hours continuously. The Yilong drone costs about US$1 million, substantially cheaper than a US unmanned aerial vehicle. It is also expected to carry out the surveillance mission more effectively than manned flights. But the Chinese army may have to improve the safety of the drones before implementing the mission, the document suggested. The report also said China’s State Oceanic Administration constantly uses nine surveillance ships and four airplanes to monitor the East China Sea area. It has 11 aerial observation bases and also uses unmanned aircraft.