The event at the Camp David presidential retreat on Friday marked the first official meeting between US President Joe Biden, his South Korean counterpart, Yoon Suk-yeol, and Japanese Prime Minister Fumio Kishida.

It comes amid thawing relations thaw between South Korea and Japan, and as the three countries have grown increasingly concerned over China’s growing assertiveness in the Asia-Pacific region as well as a string of recent North Korean missile tests.

“We are resolute in our determination to uphold regional security, strengthen Indo-Pacific engagement, and promote common prosperity,” the leaders said in a joint statement.

Speaking at a news conference alongside Kishida and Yoon on Friday afternoon, Biden hailed the work the Japanese and South Korean leaders have done to “resolve difficult issues” between their countries, and with the US.

The leaders also announced a raft of initiatives they said would further institutionalise their relationship, including boosting communication mechanisms between the three countries.

They also said they planned to set up a hotline to respond to regional crises, and pledged to hold annual trilateral meetings across government agencies.

However, the announcements on the first day of the three-day summit did not include a formal security agreement between the trio.

Washington is seeking to capitalise on a detente between South Korea and Japan, which have had fraught relations since the 1910-1945 Japanese occupation of the Korean Peninsula.

The enmity has long served as a stumbling block for Washington’s efforts to shore up support among security and economic allies in the Asia-Pacific region in its effort to counter China’s influence.

Concerns over the destabilising effect of a possible Chinese invasion of Taiwan, a self-governing island Beijing claims as its own, as well as increasing missile tests by North Korea have further heightened the need for cooperation.

Seoul and Tokyo have seen a flurry of diplomatic breakthroughs in recent months with Kishida saying earlier on Friday that he had been meeting Yoon “on a nearly monthly basis since March”.

In May, Yoon became the first South Korean leader to visit Japan in 12 years.

“From this moment on Camp David will be remembered as a historic place where the Republic of Korea, the United States and Japan proclaimed that we will bolster the rules-based international order and play key roles to enhance regional security and prosperity based on our shared values of freedom, human rights, and rule of law,” Yoon said during Friday’s news conference.

Challenges ahead

Still, analysts have noted the thaw in relations remains politically fraught, particularly in South Korea.

“The South Korean electorate is deeply divided about rapprochement, about deeper integration and collaboration with Japan,” Robert Kelly, a professor of international relations at Pusan National University in Busan, South Korea, told Al Jazeera.

“I’m not really convinced that the South Korean legislature, the National Assembly, supports this kind of engagement. And I’m not sure if the South Korean public does either.”

That underscores the need to establish long-lasting contingency plans for the myriad security and other threats in the region, Kelly said. “And that’s going to be difficult I think,” he added.

While China loomed large over the summit, the US Department of State said this week that the meeting is not meant to be “provocative” to Beijing.

Asked to comment on the possibility of enhanced security cooperation between the three countries, a spokesman for China’s Ministry of Foreign Affairs said the Asia-Pacific region “should never be turned into a wrestling ground for geopolitical competition”.

“No country should seek its own security at the expense of other countries’ security interests and regional peace and stability,” Wang Wenbin said during a news briefing.

“Attempts to cobble together various exclusionary groupings and bring bloc confrontation and military blocs into the Asia-Pacific are not going to get support and will only be met with vigilance and opposition from regional countries.”