Former Defense Minister Kim Yong-hyun, a key figure behind South Korea’s six-hour martial law chaos, is barred from leaving the country as state prosecutors, acting on a treason accusation raised by politicians, prepare for an investigation.

According to legal sources, a division of the Seoul Central District Prosecutors' Office, led by Chief Prosecutor Lee Chan-gyu, has been assigned to investigate President Yoon Suk Yeol, Kim, and Army Chief of Staff Gen. Park An-su, regarding Yoon’s emergency martial law declaration on Tuesday and the ensuing military operations.

It follows a complaint filed by the progressive Justice Party, Green Party Korea, and the Labor Party, accusing the three figures of committing treason. Gen. Park served as Martial Law Commander.

As of Thursday afternoon, prosecutors had not issued travel bans for Yoon or Park, sources said. An investigation into former Minister Kim is expected to follow.

Kim, 66, a former three-star Army general who graduated from the same high school as the president, joined Yoon’s presidential campaign team in 2022.

The presidential office confirmed Thursday that Yoon accepted Kim’s resignation as he is the one who proposed the martial law declaration to Yoon.

The same day, Vice Defense Minister Kim Seon-ho said that former Minister Kim ordered troops to infiltrate the National Assembly and prevent lawmakers from accessing the compound during martial law. The decree, which put South Korea under emergency military rule, was struck down by the opposition-controlled parliament, in a dramatic scene that saw the first infiltration of the legislature by armed troops to prevent a vote.