US President Joe Biden will meet with two of America’s closest allies to announce that Australia will buy US-made, nuclear-powered attack submarines to modernize its navy, amid growing concerns about China’s influence in the Indo-Pacific region.

Biden will travel to San Diego on Monday, where he will meet with Australian Prime Minister Anthony Albanese and British Prime Minister Rishi Sunak for talks on the 18-month-old AUKUS nuclear partnership.

The partnership, announced in 2021, paved the way for Australia’s access to nuclear-powered submarines, which are stealthy and more capable than conventional boats, as a counterweight to China’s military buildup.

San Diego is Biden’s first stop on a three-day trip to California and Nevada. He will discuss gun violence prevention in the community of Monterey Park, Calif., and his plans to lower prescription drug costs in Las Vegas.

The trip will include fundraising stops as Biden ramps up his political activities ahead of his expected plans to announce a 2024 re-election bid next month.

Australia is buying up to five Virginia-class boats as part of AUKUS, according to two people familiar with the arrangement who spoke on condition of anonymity to preview the plans. A future generation of submarines will be built in Britain and in Australia with American technology and support. Initial plans call for all Australian submarines to be built in Adelaide, Australia.

The US would also step up its port visits to Australia to give the country more familiarity with nuclear-powered technology before it has its own submarines.

Biden will also hold bilateral meetings with Albanese and Sunak, an opportunity to coordinate strategies on a range of global challenges, including Russia’s war in Ukraine and the global economy.