REUTERS/ AFPBEIJING/ TOKYOChina does not feel threatened by countries in Southeast Asia and is optimistic about the situation in the disputed South China Sea, the Foreign Ministry said, warning Japan not to “spread rumours” it plans a new air defence identification zone.China alarmed Japan, South Korea and the United States last year when it announced an air defence identification zone for the East China Sea, covering a group of uninhabited islands at the centre of a bitter ownership spat between China and Japan.Last week, Japanese newspaper the Asahi Shimbun said China was considering setting up a similar zone - where foreign aircraft are supposed to report their movements to China - in the South China Sea, prompting the US State Department to warn against such a move. In a statement released late on Saturday, China’s Foreign Ministry implied there was no need for such a zone in the South China Sea, where China, Vietnam, Malaysia, Brunei, the Philippines and Taiwan all have competing claims.“Generally speaking, China does not feel there is an air security threat from ASEAN countries,” the ministry said, referring to the Association of Southeast Asian Nations. “China feels optimistic about relations with countries surrounding the South China Sea and the general situation in the South China Sea,” the ministry said, adding it believed prospects for ties with ASEAN were “bright”.While the ministry said China had a right to set up air defence identification zones which nobody should criticise, it criticised Japan for attempting to distract attention from Japan’s own military plans.“Right wing forces in Japan have again been hyping up so-called plans that China will shortly set up an air defence identification zone in the South China Sea, which is purely to try and distract international attention, to cover up their conspiracy to ... expand their military,” the ministry said. “We warn these forces not to delude people with rumours for their own selfish interests and play up tensions, and hope the relevant party talks and acts cautiously,” it added.Ties have been strained by a recent visit by Japanese Prime Minister Shinzo Abe to a controversial shrine for war dead, China’s East China Sea air defence zone and the long-running dispute over a string of islets both countries claim, known as the Diaoyu in Chinese and the Senkaku in Japanese.China, which is swiftly ramping up military spending, has regularly dispatched patrols to the East China Sea since it established the defence zone.China has repeatedly denied Japanese accusations of being a threat to peace, saying it is Japan which is the threat, warning that Tokyo is trying to rearm and has failed to learn the lessons from its brutal behaviour during World War Two.Meanwhile, Chinese ships sailed through disputed waters off Tokyo-controlled islands on Sunday as diplomatic tension between Tokyo and Beijing intensifies.Three Chinese coastguard vessels spent more than two hours in the 12-nautical-mile territorial waters off one of the Senkakus, which China claims and calls the Diaoyus, Japan’s coastguard said.They left the waters at about 12:30 pm (0330 GMT), it said.China’s State Oceanic Administration said three of its coastguard ships were patrolling “territorial waters surrounding the Diaoyu islands” on Sunday, according to official state news agency Xinhua. It came days after a diplomatic battle over Japanese Prime Minister Shinzo Abe’s visit to a contested war shrine reached the UN Security Council, with China and Japan accusing each other of threatening stability.China’s UN ambassador, Liu Jieyi, seized upon a debate on the lessons of conflict to slam Abe for going to the Yasukuni Shrine, which honours war criminals among the country’s war dead.Last week also saw a report in Japan’s Asahi Shimbun newspaper that Chinese air force officials had drafted proposals for a new Air Defence Identification Zone (ADIZ) over the South China Sea. The United States has warned China that any move to declare a new air zone including disputed islands would be seen “as a provocative and unilateral act that would raise tensions and call into serious question China’s commitment to diplomatically manage territorial disputes,” State Department deputy spokeswoman Marie Harf told reporters.She stressed, however, that the reports were “unconfirmed” at this time.China’s foreign ministry spokesman Hong Lei said right-wing forces in Japan had repeatedly made such allegations with the intention of shifting international attention from the “plot” to change Japan’s pacifist constitution, Xinhua reported.“We sternly warned these forces not to mislead public opinions with rumours and play up tensions for their own selfish benefit,” he said in a press release Saturday quoted by Xinhua.Hong said China had the right to adopt all measures, including setting up air defence zones, to safeguard national security, according to Xinhua.Beijing claims the South China Sea almost in its entirety, even areas far from its shoreline.In November China abruptly declared an ADIZ over the East China Sea, including the disputed islands at the heart of the sovereignty row with Tokyo, sparking international criticism.Chinese state-owned ships and aircraft have regularly approached the Senkakus to demonstrate Beijing’s territorial claims, particularly after Japan nationalised some of the islands in September 2012.