Nissan would think twice before making new investments in China, the firm\'s chief told the Financial Times, as Japan-brand auto sales dive amid a territorial row between Tokyo and Beijing. Future investment in the world\'s biggest vehicle market is something that will require consideration over a period of time, Carlos Ghosn told the newspaper in an interview published Wednesday. \"Certainly beyond what we have decided, before going for further decisions in China, we will be very careful in assessing how much of an impact (the political situation) has on consumers\' minds,\" Nissan\'s top executive said. Nissan has several production plants in China with a new factory in the northeastern city of Dalian planned for 2014. Ghosn\'s comments come after Japan\'s top three automakers -- Toyota, Nissan and Honda -- scaled back production in China last month as sales plunged in the wake of a row over the sovereignty of a string of East China Sea islands controlled by Japan but claimed by China. China is Nissan\'s single biggest market, where its sales tumbled 35.3 percent to 76,066 vehicles last month. Rival Toyota saw the biggest percentage drop as September sales slumped 48.9 percent year on-year to 44,100 vehicles, while Honda\'s dropped 40.5 percent to 33,931 units. Honda, the first of the big three Japan carmakers to report its quarterly results, said Monday it was expecting an annual profit 20 percent lower than previously forecast as the territorial spat dug into sales. The island chain -- known as the Senkakus in Japan but called the Diaoyu islands by Beijing -- is located in rich fishing waters and believed to sit atop vast mineral reserves. The long-standing sovereignty dispute prompted tens of thousands of Chinese to protest last month, with some urging a boycott of Japanese products, following Tokyo\'s nationalisation of the archipelago in mid-September. Japanese factories and businesses across China closed or scaled back operations in September over fears they or their workers could be targeted by angry mobs protesting against the move.