Japan has protested to Beijing after a Chinese military vessel was detected in waters near disputed islands in the East China Sea, Reuters said on Thursday. The Chinese frigate was seen in waters contiguous to Japan’s territory around the islands, known as the Senkaku in Japan and Diaoyu in China, the Defense Ministry said. The ship did not enter Japanese territorial waters. A foreign submarine was also detected in the same area on Wednesday and Thursday, the military said, without identifying its nationality. Both had left the area by Thursday afternoon. “We want to strongly urge China not to do anything to interfere with improving bilateral ties,” Chief Cabinet Secretary Yoshihide Suga said.