President Joe Biden marked the historic summit with Japan and South Korea at Camp David on Friday by saying that “our countries are stronger and the world is safer … as we stand together.”

He described the meeting as the first standalone summit among leaders of the three countries.

Addressing South Korean President Yoon Suk Yeol and Japanese Prime Minister Fumio Kishida , Biden said, “I want to thank you both for your political courage that brought you here.”

He added: “Today will be remembered as a historic day” when they committed to the trilateral partnership.

The United States, Japan and South Korea have agreed to a new security pledge committing the three countries to consult with each other in the event of a security crisis or threat in the Pacific, according to Biden administration officials.

Details about the new “duty to consult” commitment emerged as President Joe Biden on Friday welcomed South Korean President Yoon Suk Yeol and Japanese Prime Minister Fumio Kishida for a summit at the Camp David presidential retreat in Maryland.

Before the three-way talks, Biden met separately with Yoon and then Kishida in midmorning.

The agreement is one of several joint efforts that the leaders are expected to announce at the daylong summit, as the three countries look to tighten security and economic ties amid increasing concerns about North Korea's persistent nuclear threats and China's provocations in the Pacific.

“Suffice it to say, this is a big deal," Biden's national security adviser Jake Sullivan told reporters on Friday shortly before the start of the summit. "It is a historic event, and it sets the conditions for a more peaceful and prosperous Indo-Pacific, and a stronger and more secure United States of America,"

Kishida, before departing Tokyo on Thursday, told reporters the summit would be a “historic occasion to bolster trilateral strategic cooperation” with Seoul and Washington.

“I believe it is extremely meaningful to hold a Japan-US-South Korea summit where leaders of the three countries gather just as the security environment surrounding Japan is increasingly severe,” he said.

Before it even began, the summit drew harsh public criticism from the Chinese government.

“The international community has its own judgment as to who is creating contradictions and increasing tensions,” Chinese Foreign Ministry spokesperson Wang Wenbin told reporters Friday.

“Attempts to form various exclusive groups and cliques and to bring bloc confrontation into the Asia-Pacific region are unpopular and will definitely spark vigilance and opposition in the countries of the region,” Wang said.

Sullivan pushed back against the Chinese concerns.

“It’s explicitly not a NATO for the Pacific,” Sullivan said. “This partnership is not against anyone, it is for something. It is for a vision of the Indo-Pacific that is free, open, secure and prosperous.”

The “duty to consult” pledge is intended to acknowledge that the three countries share “fundamentally interlinked security environments" and that a threat to one of the nations is “a threat to all," according to a senior Biden administration official. The official spoke on the condition of anonymity to preview the coming announcement.

Under the pledge, the three countries agree to consult, share information and align their messaging with each other in the face of a threat or crisis, the official said.

The summit is the first Biden has held during his presidency at the storied Camp David. The three leaders met for talks on Friday and were scheduled to hold a press conference later. Biden was hoping to use much of the day with the two leaders as a more informal opportunity to tighten their bond.

The US president planned to take Kishida and Yoon on a walk on the picturesque grounds and host them—and a few senior aides— for a lunch.

The retreat 65 miles (104.6 kilometers) from the White House was where President Jimmy Carter brought together Egyptian President Anwar Sadat and Israeli Prime Minister Menachem Begin in September 1978 for talks that established a framework for a historic peace treaty between Israel and Egypt in March 1979. In the midst of World War II, President Franklin Roosevelt and British Prime Minister Winston Churchill met at the retreat — then known as Shangri-La — to plan the Italian campaign that would knock Benito Mussolini out of the war.

Biden's focus for the gathering is to nudge the United States' two closest Asian allies to further tighten security and economic cooperation with each other. The historic rivals have been divided by differing views of World War II history and Japan’s colonial rule over the Korean Peninsula from 1910 to 1945.

But under Kishida and Yoon, the two countries have begun a rapprochement as the two conservative leaders grapple with shared security challenges posed by North Korea and China. Both leaders have been upset by the stepped-up cadence of North Korea's ballistic missile tests and Chinese military exercises near Taiwan, the self-ruled island that is claimed by Beijing as part of its territory, and other aggressive action.

Yoon proposed an initiative in March to resolve disputes stemming from compensation for wartime Korean forced laborers. He announced that South Korea would use its own funds to compensate Koreans enslaved by Japanese companies before the end of World War II.

Yoon also traveled to Tokyo that month for talks with Kishida, the first such visit by a South Korean president in more than 12 years. Kishida reciprocated with a visit to Seoul in May and expressed sympathy for the suffering of Korean forced laborers during Japan’s colonial rule,

The effort to sustain the trilateral relationship won’t be without challenges.

Beijing sees the tightening cooperation efforts as the first steps of a Pacific-version of NATO, the transatlantic military alliance, forming against it. U.S. officials expect that North Korea will lash out—perhaps with more ballistic missile test and certainly blistering rhetoric.

Polls show that a solid majority of South Koreans oppose Yoon’s handling of the forced labor issue that’s been central to mending relations with Japan. And many in Japan fear that bolstering security cooperation will lead the country into an economic Cold War with China, it’s biggest trading partner. Biden’s predecessor (and potential successor) Republican Donald Trump unnerved South Korea during his time in the White House with talk of reducing the US military presence on the Peninsula.

“If an ultra-leftist South Korean president and an ultra-right wing Japanese leader are elected in their next cycles, or even if Trump or someone like him wins in the U.S., then any one of them could derail all the meaningful, hard work Biden, Yoon and Kishida are putting in right now,” said Duyeon Kim, an adjunct senior fellow at the Center for a New American Security ’s Indo-Pacific Security Program.

The three leaders are also expected to detail in their summit communique plans to invest in technology for a three-way crisis hotline and offer an update on progress the countries have made on sharing early-warning data on missile launches by North Korea.

Other announcements expected to come out of the summit include plans to expand military cooperation on ballistic defenses and to make the summit an annual event. Sullivan said the leaders would commit on Friday to a multiyear planning process for joint military exercises.

The leaders are also likely to discuss the long-running territorial conflicts in the disputed South China Sea involving China, the Philippines, Vietnam, Malaysia, Taiwan and Brunei.

Earlier this month, the Philippine government summoned China’s ambassador and presented a strongly worded diplomatic protest over the Chinese coast guard’s use of water cannons in a confrontation with Philippine vessels in the South China Sea.

That tense hours-long standoff occurred near Second Thomas Shoal, which has been occupied for decades by Philippine forces stationed onboard a rusting, grounded navy ship. It is also claimed by China. (AP)