Leaders of the US, Australia and Britain are set to unveil plans to provide Australia with nuclear-powered submarines on Monday (13 March), in a major push against China’s ambitions in the Indo-Pacific.

US President Joe Biden, Australian Prime Minister Anthony Albanese and British Prime Minister Rishi Sunak will endorse details of the so-called AUKUS project, which was first announced in 2021, at the US naval base in San Diego, California, principal home port of the US Pacific Fleet.

Under the agreement, Australia will buy three US Virginia class nuclear-powered submarines in the early 2030s, with an option to buy two more if needed, US officials said.

The agreement, known as the AUKUS pact, will have multiple stages with at least one US submarine visiting Australian ports in the coming years and end in the late 2030’s with a new class of submarines being built with British designs and American technology.

The agreement will also see a force of US and British submarines deployed in Western Australia, to help train Australian crews and bolster deterrence.

China’s growing militarization of the South China Sea, which Beijing claims most of despite international maritime law that accords territory to Vietnam, Malaysia, the Philippines and other nations, is an increasing point of friction with the United States.

The United States aimed to start these rotational deployments with a single submarine in Western Australia from 2027 and within a few years it was expected to involve four US submarines and one British.

AUKUS will be the first time Washington has shared nuclear-propulsion technology since the 1950s, when it partnered with Britain. Currently no party to the nuclear Non-Proliferation Treaty other than the five countries the NPT recognizes as weapons states – the United States, Russia, China, Britain and France – has nuclear submarines.

China has condemned AUKUS as an illegal act of nuclear proliferation. In launching AUKUS, Australia also greatly upset France by abruptly cancelling a deal to buy French conventional submarines.

Big questions remain about the plan, not least over strict US curbs on the extensive technology sharing needed for the project and about the length of time it will take to deliver the submarines, even as the perceived threat posed by China mounts.

Virginia class manufacturer General Dynamics Corp has 17 submarines in its current backlog delivering through 2032.

Albanese said on Saturday that South Australia and Western Australia would be big beneficiaries of AUKUS. “This is about jobs, including jobs in manufacturing,” he said.

Britain, which left the European Union in 2020, says AUKUS will help boost its economy’s low growth rate.

Sunak said AUKUS was “binding ties to our closest allies and delivering security, new technology and economic advantage at home.”

Australia’s Defense Minister Richard Marles said last week the submarines would ensure peace and stability across the Indo-Pacific, Southeast Asia and the Indian Ocean.

Experts say that given China’s growing power and its threats to reunify with self-ruled Taiwan by force if necessary, it is vital to advance the second stage of AUKUS involving collaboration on hypersonics and other weaponry that can be deployed more quickly.