STORY: BIDEN: “AUKUS, it’s an unusual name, AUKUS, but it's a powerful entity…”

U.S. President Joe Biden, flanked by the leaders of Australia and the United Kingdom, hailed an agreement to provide Australia with nuclear-powered attack submarines in a major push to stunt Chinese ambitions in the Indo-Pacific.

BIDEN: “AUKUS has one overriding objective - to enhance the stability of the Indo-Pacific amid rapidly shifting global dynamics.”

At a U.S. naval base in San Diego, Biden on Monday laid out the so-called AUKUS plan.

BIDEN: "With the support and approval of Congress beginning in the early 2030’s, the United States will sell three Virginia class submarines in Australia with a potential to sell up to two more if needed, jump-starting their undersea capability a decade earlier than many predicted.”

The statement from the leaders said the multi-stage project would culminate with British and Australian production and operation of a "trilaterally developed" vessel based on Britain's next-generation design that would be built in the U.K. and Australia and include "cutting edge" U.S. technologies.

An Australian defense official said the project would cost the country $245 billion U.S. dollars by 2055.

UK Prime Minister Rishi Sunak:

SUNAK: "This is a powerful partnership. For the first time ever, it will mean three fleets of submarines working together across both the Atlantic and Pacific - keeping our oceans free, open and prosperous for decades to come."

China, which has been building islands and airstrips and expanding its military presence in the South China Sea, has condemned AUKUS as an illegal act of nuclear proliferation.

BIDEN: "These boats will not have any nuclear weapons of any kind on them."

Some significant questions remain about the pact: the U.S. has strict curbs on the extensive technology-sharing needed for the project. And it's not yet clear just how long it will take for Washington to deliver the submarines.