Vietnamese trawlers – some with militia on board – are intruding repeatedly into Chinese waters near the southern island of Hainan as Hanoi steps up its presence in the South China Sea , according to Chinese diplomatic observers. At least 34 Vietnamese boats sailed near Hainan between January 19 and January 31, with most of the vessels going within the 12 nautical mile territorial limit, the South China Sea Strategic Situation Probing Initiative, a think tank at Peking University, said in a report released this month. Thirty of the vessels gathered “peculiarly” on the southeast side of the island, particularly near the coast of Sanya and Lingshui, the think tank said, citing automatic identification system data used for maritime monitoring. Sanya, a city on the island, is a major base for the Chinese navy’s South Sea Fleet and home port of the aircraft carrier Shandong, while the air force uses Lingshui as a base to project power over the South China Sea. “As it is known to all, there are a number of Chinese naval and airbases,” the think tank said in the report. “It would make no economic sense for Vietnamese fishermen to go the extra distance to the east side of Hainan if simply to fish.” Malaysia, China and Vietnam in ‘dangerous, ongoing game of chicken’ in South China Sea China and Vietnam have large overlapping claims in the resource-rich South China Sea but China’s sovereignty over Hainan is not disputed, making the Vietnamese fishing activities in the area illegal, according to the think tank. Chen Xiangmiao, an associate researcher at the National Institute for South China Sea Studies in Hainan, said Vietnamese vessels made more than 10,000 such intrusions a year and the forays had continued for at least a decade. “In my observation, they do come for the fishing resources, but at the same time we do need to be aware that Vietnam has its own maritime militia on board fishing trawlers, which does not get much international attention,” Chen said. Although the military bases had their own security zones, information about the Chinese armed forces such as logistics operations, equipment details, and movements by warships and aircraft, could still be gleaned from a distance, he said. “In fact some of the Vietnamese vessels going there probably are just purely spy boats,” Chen said. He said these particular boats were usually small and hard to identify in a big fleet. “Even with the help of satellite identification systems, they are often too small and dispersed for Chinese law enforcers to catch and expel,” Chen said. Xi Jinping says China, Vietnam should resolve their disputes ‘properly’ Hu Bo, director of the Centre for Maritime Strategy Studies at Peking University, said China had held back on using force so as not to destabilise relationships with rival South China Sea claimants. In the past, tensions have risen in the region as the Chinese coastguard has sunk fishing boats from other nations, including Vietnam and the Philippines. “But if the aggression escalates it would be hard to tell [what will happen] in the future,” Hu said. China has deployed its own maritime militia – fishing boats that work with the military – in the South China Sea, engaging in confrontations with US military vessels in a number of high-profile incidents. So much so that US Navy commander Admiral John Richardson told his Chinese counterpart Admiral Shen Jinlong last year that Washington would treat the Chinese maritime militia the same as the People’s Liberation Army Navy . Purchase the China AI Report 2020 brought to you by SCMP Research and enjoy a 20% discount (original price US$400). This 60-page all new intelligence report gives you first-hand insights and analysis into the latest industry developments and intelligence about China AI. Get exclusive access to our webinars for continuous learning, and interact with China AI executives in live Q&A. Offer valid until 31 March 2020.