South Korean Defense Minister Kim Yong-hyun gave a secret order to special forces.
He called on the military to prevent the parliament from meeting to lift the martial law imposed on December 3.
South Korean Special Forces Commander Kwak Jong-geun commented on the Defense Minister's call in an interview with Yonhap.
He said he received a call on a secret telephone line from the combat control center.
The Minister stressed that he was advised not to allow more than 100-150 people to be present in the National Assembly building.
The order of the corresponding content is supposed to have come from above.
Days earlier, it was reported that South Korean police were interrogating members of the government.
A major investigation is underway over President Yoon Seok-yeol's decision to impose martial law in the country.