A US regional naval chief has warned of growing strategic uncertainty in the western Pacific, saying the 'winds of change are blowing hard' - a thinly veiled reference to Beijing's rising military power. Vice-Admiral John Bird (pictured), the departing commander of the Japanese-based US 7th Fleet, said that a peaceful status quo was 'far from guaranteed' amid growing high-stakes challenges. 'It is not all clear sailing ahead ...We find ourselves today at a pivotal juncture in the western Pacific,' he said in a strongly worded speech on Friday at the fleet's base in Yokosuka to hand command over to Vice-Admiral Scott Van Buskirk after more than two years heading the core projection of US power in Asia. 'In this remarkable period of change and in an environment of anti-access strategies and excess territorial claims, America's stabilising influence and respect for international law will be critical,' Bird said. 'Our allies will depend on the US to be fully present in the Asia-Pacific region as a promoter of stability and to ensure the free flow of commerce for all.' Bird did not mention China by name, but his references to access and territory will not be lost in Beijing or in an East Asia increasingly wary of Beijing's growing assertiveness. US defence officials have expressed repeated concerns at Beijing's increasingly strident objections to long-standing US military operations in East Asia, such as exercises with South Korea in the Yellow Sea as well as its development of ballistic missiles with manoeuvrable warheads designed to strike aircraft carriers - the traditional symbol of US military authority in the region. His comments provide a rare window into the thinking of US military operational chiefs just as the first signs emerge of a thaw in Beijing's nine-month freeze on military relations with Washington. They serve as a reminder that even if formal exchanges do restart soon, the two sides must deal with mounting differences, with the Pentagon in no mood to retreat. Differences are also sharpening over the disputed South China Sea. While Washington is avoiding taking sides in the old territorial dispute, in which Beijing claims virtually the whole area, it is appearing to support smaller claimants such as Vietnam, Malaysia and the Philippines by demanding a multi-lateral solution. Bird expressed satisfaction that, as he spoke, the USS George Washington aircraft carrier was off the Philippines and two destroyers and a nuclear submarine were heading to the Yellow Sea for exercises. 'Make no mistake, this fleet is fully engaged, very powerful, and absolutely ready,' he said, adding that US submarines were 'our ... most sensitive missions in places we cannot discuss'. He told his sailors that their efforts to shape a dynamic western Pacific would set the global stage for 100 years. He added: 'For the United States, the 7th Fleet is the centre of gravity for that effort. 'Ultimately, the challenge we face is not about any one country or ideology. It is about ensuring that all countries act responsibly within a framework that builds trust, follows international norms, avoids confrontation and promotes security. It is a challenge that demands not only constant vigilance but action, as well.' He added a quote from Irish political philosopher Edmund Burke: 'The only thing necessary for the triumph of evil is for good men to do nothing.' Bird's replacement, Van Buskirk, said his orders were simple. They were: 'Push forward, aligned to our persistent priorities - war-fighting readiness, maritime partnerships and force posture; engage with our allies and friends.'