President Yoon Suk Yeol appointed Cho Tae-yong, Korean ambassador to the US, as his new national security adviser shortly after his predecessor, Kim Sung-han, offered to resign on Wednesday afternoon.

The announcements came amid rumors that Kim could be replaced due to a protocol blunder ahead of the upcoming summit between South Korea and the US in April.

Cho's successor will be appointed "swiftly," and will ask for agreement from the US, Yoon's senior press secretary Kim Eun-hye said.

In a separate statement, Kim said he will return to Korea University, where he served as a professor of international security, US diplomatic policy and Korea-US relations before entering the office, saying that he does not want to be "a burden" to the administration.

“A year ago, when I was offered the position by the president, I said that I would return to the university after laying the groundwork for restoring the ROK-US alliance, improving Korea-Japan relations and strengthening ROK-US-Japan security cooperation,” he said in a written statement, referring to South Korea's formal name, the Republic of Korea.

“Preparations for the president's upcoming state visit to the United States are well underway, so even if a new successor arrives, I believe he or she can carry out his or her duties without a hitch."

"I hope that the controversy I have caused will no longer be a burden on diplomacy and state administration," Kim said.

Speculations erupted after several news media outlets reported that a mistake in protocol may have occurred during the preparatory process for a diplomatic event related to the Korea-US summit.

According to reports, US first lady Jill Biden, who has an interest in Korean culture, suggested a joint performance by K-pop girl group Blackpink and American pop star Lady Gaga for a state dinner during the Korea-US summit. However, it appears the proposal was not properly communicated to President Yoon, resulting in the US government reportedly demanding a response from the South Korean government on several occasions due to a lack of feedback from the presidential office.

The secretaries of protocol and diplomacy, Kim Il-bum and Lee Moon-hee, respectively, have already been replaced in recent weeks.

Diplomacy secretary Lee had been preparing for Yoon's state visit to the United States scheduled for the end of April, as well as his attendance at the Group of Seven summit in Hiroshima, Japan in May. Just before a summit was held between South Korea and Japan on March 12, protocol secretary Kim resigned, citing fatigue.