The White House on Monday announced a highly anticipated agreement to provide Australia with nuclear-powered submarines and increase submarine patrols in an effort to bolster the defense capabilities of a major ally in the Indo-Pacific region as tensions rise with China.

As part of the agreement, the U.S. will give at least three nuclear-powered Virginia-class submarines to Australia in roughly a decade.

Washington will also enhance training with Australian submariners, initiate rotational submarine patrols in the waters around Australia and work with Canberra to build a nuclear-powered submarine of its own.

President Biden is expected to formalize the security agreement at an event in San Diego with U.K. Prime Minister Rishi Sunak and Australian Prime Minister Anthony Albanese.

In a joint statement released Monday, Biden, Sunak and Albanese said the agreement “reflects the principle that shared action, taken in partnership, can benefit all.”

“Our plan elevates all three nations’ industrial capacity to produce and sustain interoperable nuclear-powered submarines for decades to come, expands our individual and collective undersea presence in the Indo-Pacific, and contributes to global security and stability,” the statement reads.

The new partnership, called AUKUS, was first announced in September 2021, emerging as a path to provide Australia with nuclear-powered submarines to augment its retiring fleet of conventional submarines while also bolstering an alliance in the Indo-Pacific to counter Chinese aggression.

Nuclear submarines are stealthier than conventional ones and would serve as a bigger deterrent to China’s maritime buildup in the Indo-Pacific.

AUKUS has infuriated Beijing, which says the partnership violates the Nuclear Non-Proliferation Treaty, a 191-nation pact that entered into force in 1970 and seeks to limit nuclear weapons productions and promote cooperation between nuclear armed nations.

AUKUS will include multiple phases to slowly build up ties between the U.S., U.K. and Australia.

Starting this year, Australian military and civilian personnel will work more closely and train with the U.S. Navy and the U.K.’s Royal Navy. Regular port visits will begin in 2023 for the U.S. and 2026 for the U.K. In 2027, the U.S. and U.K. will also begin deploying rotational submarine patrols in the waters around Australia. 

And Canberra will purchase at least three and up to five nuclear-powered submarines from the U.S., which are expected to be delivered by the early 2030s. The deal will have to be approved by Congress.

The trilateral pact also includes the construction of new “best-in-class” nuclear-powered submarines, which will be invested in by all three nations. 

Referred to as an SSN-AUKUS, the U.K. plans to build one by the end of the 2030s and Australia by the early 2040s.

To meet the demands of an upgraded fleet, Australia will expand infrastructure at a naval base in the western part of the country, HMAS Stirling, and will build a new shipyard employing thousands of workers in South Australia.

More Australian submariners will train with U.S. and U.K. personnel, along with hundreds of scientists, workers and engineers to develop skills required for building nuclear-powered submarines.

Under the arrangement, Australia is committed to never acquire nuclear weapons nor enrich uranium or construct facilities necessary to acquire nuclear weapons.The nuclear fuel provided to Canberra will be distributed in power units that will not need refueling.

China argues the supply of nuclear weapons materials to a non-nuclear state is a clear violation of the accord.

France, a NATO ally, was also upset over AUKUS because it meant the cancellation of a $66 billion contract French officials had with Australia to provide Canberra with conventional submarines.

In a briefing with reporters, National Security Adviser Jake Sullivan referred to the AUKUS deal as a “celebration” of the deepening ties among Washington, London and Canberra.

“AUKUS represents a look forward,” he said. “It is an affirmative message to all the countries in the region and frankly to the wider world as well.”

Sullivan said the Biden administration has briefed Beijing on the AUKUS deal but declined to speak on how China views the new announcement.