CAMP DAVID, Md. >> President Joe Biden and the leaders of Japan and South Korea agreed today to expand security and economic ties at a historic summit at the U.S. presidential retreat of Camp David. Their meeting and agreement come at a time when the three countries are on an increasingly tense ledge in their relations with China and North Korea.

Biden said the three countries would establish a hotline to discuss responses to threats. He announced the agreements, including what they termed the “Camp David Principles,” at the close of his talks with South Korean President Yoon Suk Yeol and Japanese Prime Minister Fumio Kishida.

“The purpose of our trilateral security cooperation is and will remain to promote and enhance peace and stability throughout the region,” they said in a joint statement.

The three leaders agreed to “improve our trilateral communication mechanism to facilitate regular and timely communication between our countries, including our national leadership,” the statement said.

“Our countries are stronger and the world will be safer as we stand together. And I know this is a belief that all three share,” Biden said as he opened the meeting.

Yoon said as the three appeared before reporters that “today will be remembered as a historic day, where we established a firm institutional basis and commitments to the trilateral partnership.”

And Kishida said before the private talks that “the fact that we, the three leaders, have got together in this way, I believe means that we are indeed making a new history as of today. The international community is at a turning point in history.”

The U.S., Japan and South Korea agreed to a new “duty to consult” security pledge committing the three countries to speak with each other in the event of a security crisis or threat in the Pacific.

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 Camp David 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 was to nu dge 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, its 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 U.S. military presence on the Korean 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.

Associated Press writers Mari Yamaguchi in Tokyo and Hyung-Jin Kim in Seoul contributed to this report.