President Moon Jae-in says that progress in denuclearization talks between North Korea and the U.S. should be a precondition for improvements in inter-Korean relations.

Moon made the comment in a written interview with the Yomiuri Shimbun daily, which was released on Tuesday on the eve of his visit to Japan for a trilateral summit with the leaders of China and Japan.

Expressing strong hopes for an agreement on the North's denuclearization at the upcoming U.S.-North Korea summit, Moon stressed that it is important to produce agreements and concrete measures to achieve complete denuclearization during the meeting. 

President Moon also expressed his willingness to cooperate with Japan over the issue of Japanese abductees in North Korea. 

He said that North Korea and Japan should seek to normalize their diplomatic ties, adding North Korean leader Kim Jong-un expressed his willingness to talk to Japan any time during the recent inter-Korean summit. 

On the South Korea-Japan relationship, Moon proposed a two-track approach -- separating economic and culture issues from historical issues, such as Japan's wartime sexual slavery.