President Lee Jae Myung said he is confident that Seoul and Washington will reach a "rational result" acceptable to both sides in their follow-up tariff negotiations, but that the process will require more time and effort.

Lee expressed optimism during an interview with CNN published on Thursday, where he discussed the possibility of signing a deal during U.S. President Donald Trump's visit to South Korea ahead of the Asia-Pacific Economic Cooperation(APEC) summit in Gyeongju next week.

The South Korean leader stressed that he bases his confidence on the two sides' alliance and the fact that they share common sense and rationality.

Seoul and Washington are currently engaged in follow-up negotiations to the trade deal they struck in July, with much focus on the method of South Korea's pledged 350 billion U.S. dollar investment in its ally's economy.

Meanwhile, Director of National Policy Kim Yong-beom and Industry Minister Kim Jung-kwan are currently in the U.S. to continue discussions with U.S. Commerce Secretary Howard Lutnick.