Japan is considering joining naval patrols in the South China Sea in a move that is likely to anger Beijing.Japan’s prime minister, Shinzo Abe, reportedly told Barack Obama during their meeting on the sidelines of the Apec summit in Manila that Tokyo was open to the idea of patrolling the area – the focus of a territorial dispute involving China and several other countries in the region – after gauging the possible impact on Japan’s security.Japanese media quoted officials as saying that Abe had told the US president he was “opposed to all unilateral attempts to change the status quo and escalate tensions”, an apparent reference to China’s construction of airfields and other facilities in the disputed Spratly archipelago.What’s behind Beijing’s drive to control the South China Sea? | Howard W French Read moreObama said he and Abe shared “an interest in continuing to foster rule of law and supporting international norms in areas like freedom of navigation and maritime law”. Japan’s chief cabinet secretary, Yoshihide Suga, confirmed the reports, but said there were no immediate plans for the country’s self-defence forces (SDF) to join US freedom of navigation operations in the South China Sea, which began in October. “At present, the SDF does not continuously conduct surveillance activities in the South China Sea, and we have no such specific plans,” Suga told reporters.Abe is also considering a request from Manila for coastguard vessels, after Japan agreed to provide the Philippines with defence equipment and technology. Speaking after the agreement, Abe said the Philippine president, Benigno Aquino, had asked Japan to provide two large patrol vessels to the Philippine coastguard.While Japan has no territorial claims in the South China Sea, it has voiced support for the Philippines and other south-east Asian countries embroiled in territorial disputes with China. It also backed Washington’s decision last month to send the USS Lassen, a guided-missile destroyer, to within 12 nautical miles of two manmade islands belonging to China.That move prompted an angry response from Beijing, which warned that that further “provocative actions” might lead to accelerated Chinese construction in the area.Ben Rhodes, the US deputy national security adviser, said Washington believed its presence in the region had a stabilising effect. “Our presence can reassure countries that these disputes are going to be solved consistent with the rules and not through one big nation bullying a smaller one,” he told reporters in Manila. Chinese development, combined with a heightened naval presence, has led to concern that Japan’s economy could be harmed by an attempt to block freedom of navigation.The region is home to major shipping lanes through which ship-borne trade worth $5tn (£3.3tn) passes every year, as well as possible oil and gas fields. China insists that its construction projects near the Spratly Islands – where its territorial claims overlap with countries including Vietnam and the Philippines – are peaceful.Any material Japanese support for countries opposing China’s territorial claims could halt a recent thaw in in ties between Beijing and Tokyo.Abe and the Chinese president, Xi Jinping, have met twice in the past year, but they have not taken advantage of recent international summits to hold more talks, apparently due to differences over Chinese activity in the South China Sea.