In the midst of international challenges, unresolved historical disagreements should not prevent South Korea and Japan from expanding ties, South Korean President Yoon Suk Yeol said on Sunday as he welcomed Japanese Prime Minister Fumio Kishida to Seoul.

The vow by the leaders to further collaboration has been hailed by the US as a strategy to better combat North Korean threats and Chinese rivalry.

Kishida’s bilateral visit, the first by a Japanese leader to Seoul in 12 years, returns the trip Yoon made to Tokyo in March, where they sought to close a chapter on the historical disputes that have dominated Japan-South Korea relations for decades.

“Cooperation and coordination between South Korea and Japan are essential not only for the common interests of the two countries but also for world peace and prosperity in the face of the current severe international situation,” Yoon said in opening remarks at their meeting.

He said unresolved historical issues should not mean that no forward steps can be taken, and that he wants to make ties better than ever.

Kishida said he hoped to discuss bilateral ties as well as regional and global issues such as North Korea with Yoon.

He has invited Yoon to the Group of Seven summit set for later this month in Japan and for trilateral talks with the U.S. on the sidelines.

Kishida will also urge for trilateral talks with China as early as this year, Kyodo reported on Friday, citing multiple unnamed diplomatic sources.

“We have a lot of opportunities to cooperate when it comes to addressing the threat of North Korea” and securing a free and open Indo-Pacific, a Japanese foreign ministry official said.

The focus of the summit between the two U.S. allies is expected to revolve around security cooperation in the face of North Korea’s nuclear threats, with a particular eye on American interests in the region, said Shin-wha Lee, a professor of international relations at Seoul-based Korea University.

“Their military and economic capabilities are crucial for promoting multilateral regional security cooperation, and a poor relationship between the two countries could obstruct U.S. objectives,” she said.