United States National Security Adviser John Bolton left for South Korea and Japan on Saturday amid a growing trade row between Seoul and Tokyo.

White House National Security Council spokesperson Garrett Marquis said on Twitter on Saturday that Bolton "departed today for Japan and South Korea to continue conversations with critical allies and friends."

Quoting a source familiar with South Korea-U.S. relations, Japan's NHK reported on Thursday that Bolton may arrive in South Korea on Tuesday for a two-day trip after visiting Tokyo.

Bolton's visit came a day after U.S. President Donald Trump said that he is willing, if needed, to help resolve escalating tensions between South Korea and Japan.

Trump said on Friday that South Korean President Moon Jae-in asked him to help resolve tensions between Korea and Japan and that he is willing, if both sides request.