Japan on Monday voiced strong regret over China\'s cancellation of ceremony to mark the 40th anniversary of the normalization of ties between the two countries amid an ongoing territorial dispute over the Japan-administrated islands. \"It is extremely regrettable that China has cancelled the ceremony,\" Chief Cabinet Secretary Osamu Fujimura told a press conference. According to Fujimura, China notified Japan on Sunday it will postpone the ceremony for the time being. The event was due to take place in Beijing on September 27. Both countries claim the small chain of uninhabited rocky islands in the East China Sea, known as Senkaku Islands in Japan and Diaoyu in China, which lie in rich fishing grounds and waters thought to contain large deposits of oil and natural gas. The cancellation is widely seen as a retaliatory measure from China against the nationalization on September 11 by the Japanese government of the islands. Earlier in the day, three Chinese surveillance vessels also entered Japanese waters near the disputed islands, prompting Tokyo to lodge a strong protest with Beijing. \"Individual issues should not affect overall bilateral relations, and it is important for the two countries to deepen strategic and mutually beneficial relationship from a broad perspective,\" the top government spokesman said. Tokyo purchased three of the five major islands from a Japanese private owner. Since the announcement two weeks ago, massive anti-Japan protests, with some cases escalating to vandalism, looting, and arson targeting Japanese factories, shops, and restaurants, erupted across China. Meanwhile, Prime Minister Yoshihiko Noda decided to send Vice Foreign Minister Chikao Kawai to Beijing from Monday to help repair relations between the two countries. Taiwan also claims sovereignty over the islands, which are known as Tiaoyutai to the Taiwanese.