The US administration of President Joe Biden is very committed to improved relations between South Korea and Japan as cooperation between the allies is key to dealing with various regional issues, including a nuclear-armed North Korea, a US diplomat said Tuesday.

Marc Knapper, deputy assistant secretary of state for Korea and Japan, also said he feels very "optimistic" about Seoul-Tokyo relations.

"I think we've seen very early on, I mean, absolute proof that this administration is committed to trilateral cooperation," Knapper said in a webinar by the Sejong Institute think tank, highlighting the importance of cooperation among South Korea, Japan and the United States.

"So we're very committed, the Biden administration is very committed to doing what we can to strengthen not just alliances but also to strengthen our trilateral cooperation, and certainly hopefully as a fringe benefit or positive outcome, that would be an improved relationship between Seoul and Tokyo," he added.

The Seoul-Tokyo relationship has deteriorated badly since mid-2019, when Japan imposed export restrictions on South Korea in apparent retaliation for Seoul's Supreme Court rulings ordering Japanese firms to compensate victims of forced labor during Japan's 1910-45 colonial rule.

Knapper said the United States understands the sensitivity and challenges posed by the history issues between its two Asian allies but stressed the need for the countries to continue working together in other fronts.

"I think our sort of consistent message to both Seoul and Tokyo will be expressing, you know, our understanding that this is a tough issue, but also, you know, our hope that while Japan and Korea address the past, they can work together on the present and the future," he said.

His remarks come after South Korean President Moon Jae-in proposed a "two-track" approach in his speech marking the 1919 Independence Movement on March 1, under which the countries will draw a clear division between history issues and other political and economic issues.

Knapper agreed the countries needed to focus on "big" pressing issues.

"We have a lot of work to do before us in that we want to ensure that whatever steps are taken to deal with the past and then deal with it in a way that promotes reconciliation. At the same time, we keep our eye on the big issues before all of us," he said.

"At any rate, I have personally seen the two countries do it before and I'm confident that with the right mixture of commitment to address problems in the past but also a pledge to deal with problems in the present and future, I think we can find a way forward." (Yonhap)