The navy has deployed several new advanced surveillance aircraft to its North Sea Fleet to hunt down submarines in the East and South China seas. The new "Gaoxin-6" maritime anti-submarine warfare planes are modified versions of the Shaanxi Aircraft Corporation's Y-8 and Y-9 medium transport aircraft and were added to the People's Liberation Army's North Sea Fleet late last year, Beijing-based naval expert Li Jie said yesterday. The military launched the Gaoxin-6 in November, 2011, and designed it to play a role similar to the United States' P-3C Orion anti-submarine aircraft. "But there is still a certain gap between China's Gaoxin-6 and the American P-3C, especially in terms of its flight and reconnaissance ranges," Li said. The North Sea Fleet is responsible for operations in the Yellow Sea, the Sea of Japan and parts of the East China Sea, as well as the Bohai Sea near Beijing. Its aviation division, dubbed the "Sea Falcons", is so far the navy's only multi-tasking force capable of air, sea and space missions, according to the latest edition of Oriental Outlook , a weekly magazine affiliated with state-run Xinhua. In addition to these missions, the Sea Falcons have started patrols over the South China Sea. "The Gaoxin-6 specialises in reconnaissance and searching for submarines," Li said. "Both Japan and South Korea have the world's most advanced submarines in the waters of the Yellow Sea and the East China Sea. That's why the navy decided to deploy Gaoxin aircraft to the North Sea Fleet first." The North Sea Fleet's multifunctional aviation division has at least five other types of advanced aircraft involved in early-warning air defence, command and control, tactical data communications and remote target designation, according to the Oriental Outlook report. "The Chinese military has developed 10 types of Gaoxin aircraft in the past decade, with four designed for the navy," Hong Kong-based military observer Leung Kwok-leung said. The Gaoxin-equipped Sea Falcons were regularly sent on missions close to disputed waters in the South and East China seas where foreign warships had been sighted, the report said Chinese and foreign aircraft over the region often came to within 20 to 30 metres of each other, with aerial encounters regularly lasting more than an hour, it said. "The PLA Navy wants to show its muscle to the US and Japanese navies, which have tried to intervene in China's territorial disputes with other Asian countries," Leung said. Li said production of the Gaoxin aircraft would be ramped up and units would be earmarked for the East Sea and South Sea fleets to defend China's territorial sovereignty.