A US nuclear submarine has arrived in Australia during a routine patrol of the region as America works to reaffirm its presence in the Pacific.
The Virginia-class USS North Carolina docked at the HMAS Stirling port in Perth on Friday after taking part in military exercises off Queensland.
It's the first time one of the nuclear-powered submarines has visited Australia since the AUKUS agreement was signed in March.
Australian Vice Admiral Jonathan Mead, US Rear Admiral Chris Cavanaugh and UK Rear Admiral Simon Asquith were on hand to greet the crew of submariners.
With them were Australia's ambassador to the US, Kevin Rudd, and Abraham Denmark, a senior advisor to the US secretary of defence for AUKUS.
Mr Denmark said more US submarines would visit Australia in coming years as the trilateral agreement, which also includes the UK, developed.
"These port visits are an essential step for Australia to build the necessary operational capabilities and skills to steward and operate its own fleet of nuclear-powered conventionally-armed submarines," he said.
"(They) serve to deepen the long-standing security and defence partnerships between the US and Australia to support a free, open and stable and secure Indo-Pacific."
Australia will buy at least three Virginia-class submarines from Washington starting in the early 2030s under the AUKUS deal.
US and British submarines will also start rotating through Australian ports from 2027.
Vice Admiral Mead said the UK and US visits would help the Royal Australian Navy develop the knowledge and expertise to operate nuclear-powered submarines.
"Australia is leveraging the more than 70 years of naval nuclear propulsion experience of our AUKUS partners as we become sovereign ready to take ownership of our own Virginia-class submarines," he said.
China has been critical of Canberra's plan to acquire nuclear submarines, most recently with Beijing's mouthpiece The Global Times accusing Australia of becoming a US military base and a "bridgehead" to attack China.
Australian Rear Admiral Brett Sonter, who is serving in the US Pacific Fleet, said China was conducting a rapid military build up as AUKUS nations worked to counter Beijing's increasing assertiveness in the Pacific.
He said he was confident the allies' submarine and anti-submarine technology were generations ahead but noted "quantity has a quality of its own" when it came to China.
"They're getting more proficient in all domains of warfare, but I'm very confident," he said.
