Claymont | President Joe Biden told Indo-Pacific allies on Saturday that he believes China's increasing military assertiveness is an effort to test the region at a turbulent moment for Beijing.

Biden's comments were caught by a hot mic after he and fellow leaders of the Quad delivered opening remarks before the press at a summit he's hosting near his hometown of Wilmington, Delaware. He said his administration sees Beijing's actions as a “change in tactic, not a change in strategy.”

China continues to struggle to pull up its economy that was pummelled by the coronavirus pandemic and has seen an extended slowdown in industrial activity and real estate prices as Beijing faces pressure to ramp up spending to stimulate demand.

“At least from our perspective, we believe Xi Jinping is looking to focus on domestic economic challenges and minimize the turbulence in China's diplomatic relationships, and he's also looking to buy himself some diplomatic space, in my view, to aggressively pursue China's interest,” Biden told Australian Prime Minister Anthony Albanese, Indian Prime Minister Narendra Modi and Japanese Prime Minister Fumio Kishida. “It is true across the scope of our relationship, including on economic and technology issues.”

Starting with a trade war that dates back to 2018, China and the United States have grown at odds over a range of issues, from global security, such as China's claims over the South China Sea, to industrial policy on electric vehicle and solar panel manufacturing.

The administration has repeatedly spoken out about concerns about Chinese military assertiveness against Taiwan and more recently on the frequent clashes between the Chinese and Philippines navies in the South China Sea. Biden recently dispatched his national security adviser, Jake Sullivan, to Beijing for three days of talks with Chinese officials. Sullivan during that visit also met with Xi.

Both governments are eager to keep relations on an even keel ahead of a change in the US presidency in January. And both sides have said they remain committed to managing the relationship, following up on a meeting between Xi and Biden in San Francisco last November.

Biden added that he continues to believe “intense competition requires intense diplomacy.”

The comments came as Biden showed off a slice of his Delaware hometown to the leaders of Australia, Japan and India as he hosted what is likely the last gathering of the Indo-Pacific partnership that has grown in prominence under his White House tenure.

When Biden began his presidency he looked to elevate the Quad, which until then had only met at the foreign minister level, to a leader-level partnership as he tried to pivot US foreign policy away from conflicts in the Middle East and toward threats and opportunities in the Indo-Pacific. This weekend's summit is the fourth in-person and sixth overall gathering of the leaders since 2021.

“It will survive way beyond November," Biden declared as the leaders gathered at the Archmere Academy, his high school alma mater in nearby Claymont for joint talks.

The president, who has admitted to an uneven track record as a scholar, also seemed tickled to get to host a gathering with three world leaders at the school he attended more than 60 years ago. He welcomed each of the leaders individually for one-on-one talks at his nearby home before they gathered at the school for talks and a formal dinner.

"I don't think the headmaster of this school thought I'd be presiding over a meeting like this,” Biden joked to fellow leaders.

Albanese, Modi and Kishida came for the summit before their appearances at the UN General Assembly in New York next week.

"This place could not be better suited for my final visit as prime minister,” said Kishida, who like Biden, is set to soon leave office.

Earlier, the president warmly greeted Kishida when he arrived at the residence on Saturday morning and gave the prime minister a tour of the property before they settled into talks. Kishida, according to the prime minister's office, thanked Biden at the outset of their meeting for inviting him to meet at his home.

White House officials said holding the talks at the president's house, which sits near a pond in a wooded area several miles west of downtown, was intended to give the meetings a more relaxed feel.

Sullivan described the vibe of Biden's one-on-one meeting with Albanese, who stopped by the house on Friday, as “two guys — one at the other guy's home — talking in broad strokes about where they see the state of the world.” He said Biden and Albanese also swapped stories about their political careers.

The Australian leader remarked that the visit had given him “insight into what in my view makes you such an extraordinary world leader.”

Modi also stopped by the house on Saturday to meet with Biden before the leaders gathered for their joint talks at Archmere.

“There cannot be a better place than President Biden's hometown of Wilmington to celebrate the 20th anniversary of the Quad,” Modi said.

As part of the summit, the leaders were set to announce new initiatives to bolster maritime security in the region — with enhanced coast guard collaboration through the Pacific and Indian oceans — and improve cooperation on humanitarian response missions. The measures are meant to serve as a counterweight to an increasingly assertive China.

Biden and Modi discussed Modi's recent visits to Russia and Ukraine as well as economic and security concerns about China. Modi is the most prominent leader from a nation that maintains a neutral position on Russia's invasion of Ukraine.

Sullivan said “that countries like India should step up and support the principles of sovereignty and territorial integrity” and that “every country, everywhere, should refrain from supplying inputs to Russia's war machine.”

Biden and Kishida, who are both stepping away from office amid sliding public support, count the tightening of security and economic ties among the US, Japan and South Korea as one of their most significant accomplishments. The two leaders sat down for their wide-ranging, one-on-one conversation on Saturday morning.

The improved relations between Japan and South Korea, two nations with a deep and complicated history that have struggled to stay on speaking terms, have come amid worrying developments in the Pacific, including strides made by North Korea in its nuclear programme and increasing Chinese assertiveness.

Biden commended Kishida for demonstrating “courage and conviction in strengthening ties” with South Korea, according to the White House. They also discussed China's “coercive and destabilising activities" in the Pacific, Russia's war against Ukraine and emerging technology issues.

The US and Japan are negotiating through a rare moment of tension in the relationship. Biden, as well as presidential candidates Kamala Harris and Donald Trump, have opposed a USD 15 billion bid by Japan's Nippon Steel to take over American-owned US Steel.

Biden administration officials indicated this week that a US government committee's formal assessment of the proposed deal has yet to be submitted to the White House and may not come until after the November 5 election.

The Biden administration promised that the leaders would issue a joint statement containing the strongest-ever language on China and North Korea to be agreed upon by the four countries.

The White House said the leaders later Saturday will rollout a new collaboration aimed at reducing cervical cancer in the Indo-Pacific. The announcement is related to Biden's Cancer Moonshot Initiative, a long-running passion project of the president and his wife, Jill Biden, aimed at reducing cancer deaths. The Bidens' son Beau died in 2015 at age 46 of brain cancer.