South Korean President Lee Jae Myung, in his first summit with Japanese Prime Minister Shigeru Ishiba on Saturday, stressed the importance of setting aside their past differences as they face common challenges from the United States, their mutual ally.

The two agreed to cooperate in areas that include clean energy, artificial intelligence, low birth rates, an aging population and disaster prevention.

They reaffirmed that South Korea and Japan would work together and with the United States toward ending North Korea’s nuclear and missile development programs.

Lee's visit to Japan may help him prepare for his crucial first summit in Washington on August 25 with U.S. President Donald Trump, where both sides are mainly set to discuss trade and defense issues.

Lee — who met Ishiba on the sidelines of the Group of Seven summit in June — said he was the first South Korean president since the 1965 normalization of the bilateral ties to choose Japan as a first destination for a bilateral summit after taking office.

Japanese officials see it as a sign of Lee placing great importance on relations between the two neighbors whose ties have repeatedly been disrupted by historical disputes, hampering their trilateral coordination with Washington.

For Ishiba, who faces pressure from rightwing rivals within his governing party to resign over its July election loss, Lee’s visit could also be a boost.

Saturday’s summit was aimed at highlighting the two nations' good ties as this year marks the 60th anniversary of normalizing their diplomatic relations.