Beijing: An unprecedented joint China-Russia bomber patrol over disputed territory off the coast of South Korea and Japan was a “massive development” in their bid to challenge US influence in the region, analysts said Wednesday. The joint patrol caused outcry from Washington´s two main allies in the region after both Tokyo and Seoul claimed a Russian plane violated their airspace. Seoul said a Russian warplane twice entered South Korean airspace near the disputed Dokdo islets — which Tokyo also claims and calls Takeshima — and that it fired warning shots in return. Japan also said it scrambled fighter jets in response. “It´s a big deal because it displays confidence that the air forces of the two nations can coordinate a patrol of this nature in ways that the region will almost certainly find destabilising,” said Lyle Morris, senior policy analyst at RAND Corporation. China and Russia have increasingly close ties and have conducted a number of joint military exercises, but this bears extra political significance for taking place over disputed islands which are a source of simmering diplomatic friction between Japan and South Korea. Ahn Chan-il, a researcher in Seoul, told AFP the violation of the disputed airspace was “deliberate”. “China and Russia are seeking to counterbalance Washington when it comes to North Korea´s nuclear issues,” he told AFP. “(They) are causing trouble in order to gain dominance in the region by provoking Washington´s two key allies.” Both Moscow and Beijing have denied the exercise targeted other countries or violated disputed airspace, but the move was a bold one, say analysts, which targeted the region´s two main US allies at the same time. Adam Ni, China researcher at Macquarie University in Sydney, said it was also significant that the bombers involved — two Chinese H-6Ks and two Russian Tu95s — were nuclear-capable, “so it´s sending an additional message”. “I think that is a fairly massive development in terms of the regional security landscape,” he said. ‘Challenge to the US’ Trade between Moscow and Beijing was up 25 percent in 2018 to hit a record $108 billion, and Chinese President Xi Jinping described Russian counterpart Vladimir Putin as his “best friend” at a June meeting. But analysts say the cooperation is moving beyond economic ties towards a wider partnership to upset the status quo. “It also signals that Russian-PRC jointness has reached sufficient maturity that they can now conduct joint patrols,” said J. Michael Cole, a Taipei-based senior fellow with the Global Taiwan Institute in Washington. “This, in my view, constitutes a direct challenge to the US alliance system in the Indo Pacific.” The joint patrols also came a day before China unveiled its national defence plan, in which it spoke of the need to develop alternative military capabilities beyond sheer manpower. China has the biggest army in the world and has the second-highest spending after the US, but the plan said warfare was evolving towards “intelligent” combat, citing a growing use of artificial intelligence, big data, cloud computing and new high-tech military technologies. Senior Colonel Wu Qian, a Beijing defence ministry spokesman, said the joint exercises would “push the Sino-Russian military relations in the new era to a new historical height”. But the partnership between the two is not necessarily easy. Ni said that while the two powerhouses “in a way still do not trust each other”, they “have a common perceived security challenge in the United States”. Analysts expect to see more joint operations in the future. “This is also a natural offshoot of growing joint military exercises between Russia and the PRC in recent years,” said Cole. “It says, ´if the US, Japan and ROK (South Korea) can do such things, why not us´?”