National Security Adviser Kim Sung-han has resigned following media reports speculating that the top office may replace him over a planning issue related to President Yoon Suk Yeol's state visit to the U.S. 

In a statement released to the media on Wednesday, Kim said that he hopes controversy surrounding him would no longer burden the administration in running state affairs.

Kim said that when he was offered the position by Yoon a year ago, he told the president that he would return to school after restoring the South Korea-U.S. alliance, improving Korea-Japan relations, and laying the groundwork for strengthening security cooperation among South Korea, the U.S. and Japan.

Kim said that he believes these conditions have been met to some extent.

He added that as preparations for Yoon's trip to the U.S. are well under way, his successor should be able to carry out work without any problems. 

The resignation came after the top office recently replaced a presidential aide on foreign affairs and a presidential protocol secretary.

Media outlets speculated that in the process of coordinating the schedule and events for Yoon's planned state visit to the U.S., there had been omitted reports to the president.