US President Joe Biden on Friday sealed new security cooperation with Japan and South Korea as he hosted the leaders of the Asian countries in three-way talks at Camp David.

"We, the leaders of Japan, the Republic of Korea (ROK), and the United States, convened at Camp David to inaugurate a new era of trilateral partnership," a statement released by the White House said.

"We do so at a time of unparalleled opportunity for our countries and our citizens, and at a hinge point of history, when geopolitical competition, the climate crisis, Russia's war of aggression against Ukraine, and nuclear provocations test us," the statement added.

Biden also praised the "political courage" of South Korean President Yoon Suk Yeol and Japanese Prime Minister Fumio Kishida in turning the page on their historical animosity.

Japan and South Korea have had strained relations dating back to Japan's 1910-1945 occupation of Korea.

What is the new security cooperation deal?

The three nations have agreed to a new security pledge committing them to consult with each other in the event of a security crisis or threat in the Pacific.

Under the pledge, the three allies agreed to share information via an emergency hotline between Washington, Tokyo and Seoul, according to the White House.

The security pledge comes against the backdrop of China's recent assertiveness in the Indo-Pacific region, particularly Beijing's vow to retake the autonomous island of Taiwan by force, if necessary.

The leaders issued a sharply worded statement about Beijing's actions in the South China Sea, where China has claimed territory that according to international law, belongs to other countries. China has also pledged to conduct military exercises in the region, which could further escalate tensions.

"Regarding the dangerous and aggressive actions we recently witnessed by the People's Republic of China in support of its illegal maritime territorial claims in the South China Sea, we ... strongly oppose any attempt to unilaterally change the status quo in the Indo-Pacific waters," the statement said.

Despite the tensions between Washington and Beijing, Biden did, however, say he expects to meet Chinese President Xi Jinping later this year.

The US, Japan and South Korea also agreed to set up an "early warning system" to share information and coordinate on "possible disruptions to global supply chains as well as to confront and overcome economic coercion."

North Korea threat highlighted

One of several regional security challenges discussed during the Camp David talks was North Korea.

The three leaders spoke forcefully in remarks to reporters about Pyongyang's nuclear and other threats and said they would cooperate to counter them.

They agreed to hold trilateral military training exercises annually and to share real-time information on North Korean missile launches by the end of 2023.

The three allies promised to hold trilateral summits annually.

Last month, Russia and China attended a military parade in Pyongyang, marking the 70th anniversary of the end of the Korean War.

Nuclear-capable missiles and new attack drones were among the weapons on display, according to state media.

Meanwhile, on Friday Japan's military said it had scrambled fighter jets after Russian patrol aircraft were detected off the Sea of Japan and the East China Sea.

Fukushima water issue not addressed

While at Camp David, Kishida said he would make a final decision on Sunday on whether to release 500 Olympic-size swimming pools worth of water from the Fukushima nuclear power plant into the Pacific Ocean.

"The government is at the final stage of when it has to make a decision," Kishida said after the meeting with Biden and Yoon.

Although the International Atomic Energy Agency (IAEA) greenlit the plan last month, sources told the Reuters news agency that Tokyo had so far held off going through with it to avoid creating geopolitical tensions ahead of the Camp David talks.

South Korea has repeatedly condemned the plan, as has China,

After the talks on Friday, Yoon said that the Fukushima issue was on the agenda and was not addressed.