At least 60 American warplanes conducted close-up reconnaissance flights near China in September and the US may be preparing for future long-distance missions in the South China Sea , according to a think tank in Beijing. Among the 60 warplanes recorded, 41 flew over the disputed South China Sea, six over the East China Sea and, further north, 13 over the Yellow Sea, the Chinese government-backed South China Sea Strategic Situation Probing Initiative (SCSPI) said in a report released on Monday. The report said air refuelling activities had shown an uptick last month, possibly suggesting the United States was preparing for future long-distance attacks against targets in the South China Sea. It said several air refuelling aircraft sent to add fuel to the surveillance planes over the South China Sea had departed from the US’ military base in its western Pacific island territory of Guam. “It‘s unusual for the US to dispatch fuel tankers from Guam [instead of from Kadena airbase in Japan] because such operations are uneconomical and inefficient,” the report said. “Such operations are more probably preparing for future long-distance refuelling in extreme conditions, and thus deserve great attention. “This showed that the South China Sea region is still the US’ primary focus, but what is equally notable is that activities in the Yellow Sea region had a marked increase when compared with the sporadic activities two months ago,” the report said. The warplanes typically carry out two kinds of reconnaissance flights: routine and specific. The former are more predictable, given their set pattern of plane type, frequency and region. Of the specific reconnaissance flights, 13 planes flew to the Yellow Sea and three to the East China Sea while the Chinese military was conducting drills , according to the report. The total number of flights was roughly the same as in July and August, the report said, adding that the real numbers may have been higher because some warplanes disguised themselves as civil planes or did not turn on transponders. The report highlighted the danger of such disguised spying activities, with six US planes having spied on Chinese military activities while using false civil aircraft codes. In late September, a US Air Force plane changed its aircraft identification code as it flew over the Yellow Sea, making it resemble a Philippine aircraft, before reverting to its original number after completing its mission, the SCSPI said. Also in September, American RC-135S planes electronically disguised themselves as Malaysian civilian aircraft while flying close to Chinese airspace, the SCSPI said. The switch was also reported by Popular Mechanics magazine. Beijing said in August that flying in disguise was putting civilian aircraft at risk. In 1983, the Soviet Air Force shot down a Korean Airlines passenger jet in its airspace, killing all 269 on board, after misidentifying it as an intruding US spy plane. US puts record number of eyes in the skies off China coast in July Ben Ho, an associate research fellow at the S. Rajaratnam School of International Studies in Singapore, said the use of the Guam base showed the US military was planning for a worst-case scenario. “The US deployment of aerial tankers from Guam rather than Okinawa hints at the much talked-about contingency where bases on the Japanese island are knocked out by Chinese missiles during the opening stages of a Sino-American conflict,” Ho said. “[It] also shows that Washington is hedging against the possibility that Japan refuses US forces [being] stationed on its soil to be deployed against China. Under these two circumstances, America has no choice but to fall back to Guam.” But Ho added: “While there is much talk about the dangers posed by unsafe encounters between US and Chinese forces in the air or even at sea, the potential for escalation in such situations is low.” Malcolm Davis, a senior analyst specialising in Chinese security at the Australian Strategic Policy Institute in Canberra, said the US needed to step up its presence to deter China from engaging in regional aggression, including in the South China Sea. “My biggest worry is that China will seek to exploit any internal unrest or political distraction in the US following the US presidential election, to move aggressively against Taiwan or in the South China Sea,” Davis said. “The US has to deter such an act, and these types of training missions are part of that – forward presence and resolve being communicated to Beijing.”