Her Majesty's Australian Ship (HMAS) Rankin, the sixth submarine of the Collins class, underway

The United States announced a new alliance Wednesday with Australia and Britain to strengthen military capabilities in the face of growing rivalry with China, including a new Australian nuclear submarine fleet and cruise missiles.

The announcement of the alliance -- made in a video meeting by President Joe Biden, Australian Prime Minister Scott Morrison and his British counterpart Boris Johnson -- is sure to raise hackles in Beijing.

It also met with swift pushback from France, which has been negotiating a multi-billion-dollar sale of conventional submarines to Australia.

Biden said the work to enable Australia to build nuclear-powered submarines would ensure that they had "the most modern capabilities we need to manoeuvre and defend against rapidly evolving threats."

The submarines, stressed Biden and the other leaders, will not be nuclear armed, only powered with nuclear reactors.

Morrison later announced Australia would also acquire long-range US Tomahawk cruise missiles.

The three leaders did not mention China in unveiling the partnership, dubbed AUKUS, but their intent was clear.

"Our world is becoming more complex, especially here in our region, the Indo-Pacific. This affects us all. The future of the Indo-Pacific will impact all our futures," Morrison said.

Johnson said they would work "hand in glove to preserve stability and security in the Indo-Pacific."

On a visit last week to Southeast Asia, Vice President Kamala Harris accused Beijing of "actions that... threaten the rules-based international order," particularly its aggressive claims in the South China Sea, where frequent territorial disputes have erupted between China and its neighbours in recent years.

Technical and naval representatives from the three countries will spend the next 18 months deciding how to carry out Australia's upgrade, which Johnson said would be "one of the most complex and technically demanding projects in the world, lasting for decades."

In addition to the submarine fleet, a senior Biden administration official said AUKUS will combine forces on "cyber, AI -- particularly applied AI -- quantum technologies and some undersea capabilities as well."

The Biden administration official underlined repeatedly how "unique" the decision is, with Britain being the only other country the United States has ever helped to build a nuclear fleet.

"This technology is extremely sensitive," the official said. "We view this as a one-off."

- Stealth and interoperability - With China building up its own navy and repeatedly testing decades of US military dominance across Asia, the creation of AUKUS, with its focus on submarines, is "meant to send a message of reassurance and a determination to maintain a strong deterrent stance," the US official said.

Even if not carrying nuclear weapons, the new submarines will allow Australia to "play at a much higher level," the official said.

"Nuclear powered submarines really maintain superior characteristics of stealth, speed, manoeuvrability, survivability and really substantial endurance," the official said.

"You will see much deeper interoperability along our navies and our nuclear infrastructure," the official said. "This is a fundamental decision, fundamental. It binds Australia... and the United States and Great Britain for generations."

- French deal over - Biden, in an attempt to placate Paris, said France is a "key partner and ally" in the Indo-Pacific.

But the new alliance torpedoed Australia's conventional submarine deal with France, which had been personally backed by President Emmanuel Macron.

Morrison confirmed on Thursday morning Australia would not proceed with the deal.

France's foreign ministry said in a statement earlier that the decision to go with US submarines was "contrary to the letter and the spirit of the cooperation that prevailed between France and Australia."

The submarine contract with France was worth around Aus$50 billion (31 billion euros, 36.5 billion dollars) at the time of signing. More recently the overall deal was estimated at some Aus$90, taking into account currency fluctuations and cost overruns.

The company had agreed to build 12 conventional Attack Class subs, but the order was years behind schedule, well over budget and has become tangled in Australian domestic politics.

The AUKUS announcement comes as Australia has been boosting defence spending in response to China's more assertive posture.

Morrison will join Biden again on September 24, this time in person, at a first White House gathering of the "Quad" diplomatic group -- Australia, India, Japan and the United States.