Chinese patrol vessels entered waters claimed by both China and Japan on Wednesday, intensifying tensions between the two nations over the disputed islands in the East China Sea, The Wall Street Journal reported. According to the Japanese Coast Guard, a Chinese patrol vessel came within 22 kilometers of the Senkaku Islands early Wednesday morning and two others also entered waters claimed by Japan. “Our vessel is conducting official duties within China’s territorial waters. Do not obstruct. Leave the Chinese waters immediately,” one of the vessels was reported as saying, according to the Coast Guard release. The vessels are said to have retreated after repeated warnings from Japanese Coast Guard officials. Fearing trade repercussions, Japanese Foreign Minister, Koichiro Gemba, called for a “coolheaded response” from both nations.