Lee Rae-kyung, the honorary chair of the progressive grassroots advocacy group The Tomorrow, offered to resign from his role to lead the reform of the main opposition Democratic Party of Korea, about 10 hours after his nomination Monday.

Lee's decision comes following controversy in political circles over past pro-North Korea remarks, which surfaced immediately after the news of his nomination.

"I regret that a private opinion ... has become the subject of a political witch-hunt," Lee said in a statement via the Democratic Party.

"From my point of view, (the controversy) explains the reality of Korean society, but I would like to offer to (resign) from the (Democratic Party's) body to initiate party reform because the prolonged controversy surrounding myself would put pressure on the Democratic Party."

Lee in February described the United States as "the culprit behind the impediment to the detente between North Korea and South Korea by manipulating facts about the sinking of Cheonan" on a social media post, as he claimed the United States had exaggerated the role of Chinese high-altitude balloons that were shot down by US forces as "national threats."

In 2010, Cheonan, a South Korean Navy corvette, capsized as a result of an explosion, claiming the lives of 46 seamen. Investigators from six countries including South Korea concluded that a North Korean torpedo from a submarine had sunk the ship, but some progressive figures have long denied North Korea's involvement in the incident.

This stands in contrast with Rep. Lee Jae-myung, chairman of the Democratic Party, who earlier admitted that North Korea had sunk the ship. Lee told reporters that he "was not fully aware" of the nominee's remarks over the Cheonan sinking.

Nominee Lee in 2020 also claimed that the United States was the origin of the coronavirus that caused the worldwide COVID-19 pandemic.

Chairman Lee announced at a Supreme Council meeting held at the National Assembly Monday morning that nominee Lee will be in charge of leading the party's new innovation committee designed for party-wide reform.

The opposition party has sought a breakthrough with the new committee as chairman Lee himself is facing multiple criminal charges, including over his alleged involvement in a high-profile land corruption scandal in southern Gyeonggi Province and over false statement during a presidential election campaign where he was defeated by President Yoon Suk Yeol in 2022. Most recently, attorney-turned-lawmaker Rep. Kim Nam-kuk was found to have owned a lump sum of cryptocurrency -- an asset he did not declare to the public -- while trading crypto assets during parliamentary sessions.