The Defense Security Command (國軍機務司令部, English: Defense Security Command, DSC), or simply the Gimu-sa (機務司), was an investigative and intelligence agency under the direct control of the Ministry of National Defense of South Korea, which moved from Samcheong-dong 25-1, Jongno-gu, Seoul, to Gwacheon,
Founded~Dissolved May 27, 1948 ~ Sep 1, 2018Last edited Oct 15, 2026, 2:51 PM
Defense Security Command (國軍機務司令部, English: Defense Security Command, DSC), or simply the Gimu-sa (機務司), was an investigative and intelligence agency under the direct control of the Ministry of National Defense of South Korea, which moved from Samcheong-dong 25-1, Jongno-gu, Seoul, to Gwacheon, Gyeonggi Province. Its stated purposes were collecting military intelligence, military security and counterintelligence, and criminal investigation, but in practice it arrested people who opposed the government, tortured them, and caused some to die.1 However, since the days of the Armed Forces Security Command, it regarded those who criticized the Park Chung-hee, Chun Doo-hwan, and Roh Tae-woo regimes or who took part in protests and student movements as subversive elements, and took them away without exception, subjecting them to water torture, electric torture, the "roast chicken" position, and beatings with sleep deprivation. It also attempted assassinations overseas. Park Chung-hee and Chun Doo-hwan were involved in problems such as interfering in politics and instigating military coups. The unit consisted of a headquarters and support units; the support units were assigned to regiment-level or larger units of the armed forces but operated as independent units separate from the units to which they were assigned.
On August 6, 2018, it was confirmed that it would be named the Military Security Support Command. The reorganization plan was deliberated and approved at the State Council on August 14.23
On September 1, 2018, with the launch of the Military Security Support Command, which performs military intelligence, security, and counterintelligence functions, the Defense Security Command, which had caused controversies over surveillance of the families of the Sewol ferry victims, manipulation of public opinion, and preparations for martial law, was dissolved.
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In November 1945, an intelligence section was established within the Defense Headquarters of the U.S. Army Military Government in Korea, and in January 1946 it was reorganized into the intelligence section of the South Korean National Defense Constabulary. On May 27, 1948, the "Special Investigation Section," established within the intelligence office of the Joseon Constabulary, served as its parent body. After the government was established, in November 1948 it was reorganized as the "Special Investigation Unit" of the Army Headquarters Intelligence Bureau, and in October 1949 as the "Counterintelligence Unit." After the outbreak of the Korean War, in October 1950 it became independent from the Intelligence Bureau as the "Special Operations Unit" (特務部隊, Special Operation Unit, SOU), directly under the Army Headquarters. Due to problems including civilian massacres, political surveillance, and abuse of power and arbitrariness, after the April 19 Revolution it was renamed in July 1960 as the Army "Counterintelligence Corps" (防諜部隊, Korean Counterintelligence Corps, KCIC),5 and in September 1968 it was renamed the Army "Defense Security Command" (Defense Security Command).
Navy and Air Force
In 1953, the Navy Counterintelligence Unit was established, and in 1954 the Air Force Special Investigation Unit was established, respectively.
The Gimu-sa had been located at the Seoul Regional Hospital since the days of the Armed Forces Security Command, and in November 2008 it moved to Gwacheon, Gyeonggi Province.
Dissolution
In 2018, when it became known that the Defense Security Command had engaged in activities during the Lee Myung-bak administration to Park Geun-hye administration, including manipulation of public opinion, surveillance of the Sewol ferry victims' families, and preparations for martial law, and controversy arose, President Moon Jae-in ordered the dissolution and restructuring of the Gimu-sa. On September 1, 2018, the Ministry of National Defense dissolved the Defense Security Command at 30 Samcheong-ro, Jongno-gu, Seoul, Special City, and established the Military Security Support Command, a new military security unit.
Duties
Security and management of military secrets within the armed forces
Collection, preparation, and processing of domestic military-related intelligence
Protection posture for information operations and support for information warfare
Matters concerning the investigation of crimes stipulated in Article 44, Paragraph 2 of the Military Court Act
Protection support for defense-sector critical information and communication infrastructure among the critical information and communication infrastructure designated under Article 8 of the Information and Communications Infrastructure Protection Act
Communications interception
Controversies and criticism
When the public opinion manipulation, activities related to the Sewol ferry, and review of martial law during the Lee Myung-bak and Park Geun-hye governments came to light, about 80% of the public was found in polls to support abolishing the Gimu-sa or thoroughly reforming it. According to a RealMeter poll, 44.3% responded with thorough reform, 34.7% with abolition, 11.3% with maintaining the status quo, and 9.7% with "don't know." Even among supporters of the Liberty Korea Party, 41.7% responded with thorough reform, 6.3% with abolition, and 37.4% with maintaining the status quo, showing that opinion favoring thorough reform prevailed.8
Stalled investigation of secret leaks
The Defense Security Command detected that military secrets were being leaked by senior officers at the Navy Education Command by bypassing the military security program guards, and has been investigating for nearly a year. However, it has not found concrete evidence related to the leaks, and the investigation has run into difficulties. An insider filed a complaint again after retirement with the Anti-Corruption and Civil Rights Commission, a different government agency. Nevertheless, the investigation remained sluggish, and when the National Defense Committee's parliamentary audit opened in October 2014, the matter was placed on the official agenda and received serious criticism. For this reason, there are concerns both inside and outside the military that the sensitivity of the leaked material may be affecting the investigation.9
Concealment of internal sexual crimes
In July 2018, the Gimu-sa received a report from a female non-commissioned officer that she had been raped by a colleague. However, the Gimu-sa concluded that no rape had occurred and that it had been sexual intercourse by mutual agreement. The Military Human Rights Center and the female non-commissioned officer could not accept this, and reported to the Ministry of National Defense Investigation Headquarters, but no conclusion was reached, and the woman who claimed to be the victim retired.10
Manipulation of public opinion
Rep. Lee Chul-hee of the Democratic Party released a document that the Gimu-sa had reported to the Blue House on June 4, 2008, when the Lee Myung-bak government took office. In the document, after reviewing the status of "cyber personnel by agency," including the National Intelligence Service, the National Police Agency, the Joint Chiefs of Staff, and the Gimu-sa, the Gimu-sa proposed the operation of a non-public special team whose mission was "to respond to left-wing anti-government propaganda and agitation and to spread public opinion supporting the government." It also presented step-by-step activities: responding to left-leaning articles and columns, publicity through seminars, criticizing illegal activities of the left, and educating and organizing university students.11
In connection with the public opinion manipulation case, the Ministry of National Defense's General Court-Martial announced that it had issued an arrest warrant for a former Gimu-sa lieutenant colonel who is suspected of involvement in the Defense Security Command's public opinion manipulation activities and of publicly expressing political opinions.12
Activities related to the Sewol ferry disaster
During the Park Geun-hye administration, for six months immediately after the Sewol ferry disaster, the Gimu-sa compiled the personal information of the missing persons' families and representatives of the family support committee, classified their leanings, attempted to eradicate the families' "unreasonable demands" by conveying national criticism to them, and deployed Gimu activity officers to Paengmok Port and Danwon High School, reporting to it daily. In addition, the Gimu-sa provided conservative groups with documents on Sewol-related assembly information so that they could hold rallies to counter the assemblies held by civic groups.13
In September 2014, the Gimu-sa developed logic and methods to persuade the families of the missing to end the search, and the document states that this logic and these methods were "Blue House reporting items."14
The independent investigation team to examine the martial law allegations is expected to also investigate suspicions of surveillance of the Sewol ferry victims' families. Kim Eui-kyeom, spokesperson of the Blue House, said, "The President has instructed the independent investigation team to also investigate the suspicions of the Gimu-sa's surveillance of the Sewol victims' families."15
On August 2, the Ministry of National Defense Special Investigation Team (hereinafter the "Special Team") confirmed, from a USB drive related to the Gimu-sa's martial law documents, content on "preparations for implementing martial law" as well as the fact of surveillance of the Sewol victims' families. The Special Team stated, "After the Sewol disaster, the Gimu-sa formed a Sewol task force under the pretext of on-site support and, in addition to general support duties, carried out surveillance of the victims' families," and "we confirmed that through on-site and cyber surveillance, it collected and reported information on the families' leanings, their reactions to government announcements, photos of the families, educational backgrounds, and phone numbers."16
Review of martial law declaration against candle-light protests during the Park Geun-hye government
This was an incident in which, in connection with the impeachment trial of President Park Geun-hye, plans were prepared to issue garrison decrees and martial law in the event that the impeachment was dismissed or rejected. The Liberty Korea Party stated that these Gimu-sa actions were duties for contingencies, and took the position that "whether the Gimu-sa exceeded its authority should be examined, but if the military does not prepare to this extent in a situation where candle-light protest participants and Taegukgi rally participants are in confrontation, it is neglecting its duties."17 On the other hand, the government, the Democratic Party, the Bareunmirae Party, and the Justice Party are pursuing punishment of those involved in drafting the documents, searches of each unit, National Assembly hearings, as well as abolition of the garrison units established in metropolitan cities and provinces, demotion of the Gimu-sa commander's rank, and reduction of personnel.18
Chiefs of staff without command authority over counterintelligence units
The organization was subordinate to the Minister of National Defense and the President, and the chiefs of staff had no authority to command the Defense Security Command.19 Chun Doo-hwan, the first lieutenant who had drawn out the decisive clue for the success of the May 16 coup, was dispatched as personnel section chief to the creation of the Central Intelligence Agency,19 and President Park Chung-hee managed the military chain of command by dividing it into two systems: the official chain of command under the chief of staff and the intelligence system under the Defense Security Command commander.20
Due to the conflict between Chung Seung-hwa, the martial law commander and chief of staff, and the identity of Chun Doo-hwan and his subordinates, dissatisfaction arose over Chung Seung-hwa's personnel appointment of Major General Jang Tae-wan as commander of the Capital Garrison Command. This dissatisfaction was also conveyed to Kim Jong-pil, chairman of the Democratic Republican Party.21 Kim Jong-pil believed that the fact that dissatisfaction with military personnel had reached even the political sphere was a problem of control over the military from the official chain of command.21
Past commanders
Since 1991, the commander of the Gimu-sa has held protocol precedence among the three-star generals of the Republic of Korea Armed Forces immediately after the commander of the Republic of Korea Marine Corps, and ranks tenth among active-duty servicemembers.
Footnotes
Footnotes
“국군기무사령부령”. 《국가법령정보센터》. Ministry of Government Legislation, Republic of Korea. Accessed July 8, 2018. ↩
Defense Security Command (國軍機務司令部, English: Defense Security Command, DSC), or simply the Gimu-sa (機務司), was an investigative and intelligence agency under the direct control of the Ministry of National Defense of South Korea, which moved from Samcheong-dong 25-1, Jongno-gu, Seoul, to Gwacheon, Gyeonggi Province. Its stated purposes were collecting military intelligence, military security and counterintelligence, and criminal investigation, but in practice it arrested people who opposed the government, tortured them, and caused some to die.1 However, since the days of the Armed Forces Security Command, it regarded those who criticized the Park Chung-hee, Chun Doo-hwan, and Roh Tae-woo regimes or who took part in protests and student movements as subversive elements, and took them away without exception, subjecting them to water torture, electric torture, the "roast chicken" position, and beatings with sleep deprivation. It also attempted assassinations overseas. Park Chung-hee and Chun Doo-hwan were involved in problems such as interfering in politics and instigating military coups. The unit consisted of a headquarters and support units; the support units were assigned to regiment-level or larger units of the armed forces but operated as independent units separate from the units to which they were assigned.
On August 6, 2018, it was confirmed that it would be named the Military Security Support Command. The reorganization plan was deliberated and approved at the State Council on August 14.23
On September 1, 2018, with the launch of the Military Security Support Command, which performs military intelligence, security, and counterintelligence functions, the Defense Security Command, which had caused controversies over surveillance of the families of the Sewol ferry victims, manipulation of public opinion, and , was dissolved.
In November 1945, an intelligence section was established within the Defense Headquarters of the U.S. Army Military Government in Korea, and in January 1946 it was reorganized into the intelligence section of the South Korean National Defense Constabulary. On May 27, 1948, the "Special Investigation Section," established within the intelligence office of the Joseon Constabulary, served as its parent body. After the government was established, in November 1948 it was reorganized as the "Special Investigation Unit" of the Army Headquarters Intelligence Bureau, and in October 1949 as the "Counterintelligence Unit." After the outbreak of the Korean War, in October 1950 it became independent from the Intelligence Bureau as the "Special Operations Unit" (特務部隊, Special Operation Unit, SOU), directly under the Army Headquarters. Due to problems including civilian massacres, political surveillance, and abuse of power and arbitrariness, after the April 19 Revolution it was renamed in July 1960 as the Army "Counterintelligence Corps" (防諜部隊, Korean Counterintelligence Corps, KCIC),5 and in September 1968 it was renamed the Army "Defense Security Command" (Defense Security Command).
Navy and Air Force
In 1953, the Navy Counterintelligence Unit was established, and in 1954 the Air Force Special Investigation Unit was established, respectively.
The Gimu-sa had been located at the Seoul Regional Hospital since the days of the Armed Forces Security Command, and in November 2008 it moved to Gwacheon, Gyeonggi Province.
Dissolution
In 2018, when it became known that the Defense Security Command had engaged in activities during the Lee Myung-bak administration to Park Geun-hye administration, including manipulation of public opinion, surveillance of the Sewol ferry victims' families, and preparations for martial law, and controversy arose, President Moon Jae-in ordered the dissolution and restructuring of the Gimu-sa. On September 1, 2018, the Ministry of National Defense dissolved the Defense Security Command at 30 Samcheong-ro, Jongno-gu, Seoul, Special City, and established the Military Security Support Command, a new military security unit.
Duties
Security and management of military secrets within the armed forces
Collection, preparation, and processing of domestic military-related intelligence
Protection posture for information operations and support for information warfare
Matters concerning the investigation of crimes stipulated in Article 44, Paragraph 2 of the Military Court Act
Protection support for defense-sector critical information and communication infrastructure among the critical information and communication infrastructure designated under Article 8 of the Information and Communications Infrastructure Protection Act
Communications interception
Controversies and criticism
When the public opinion manipulation, activities related to the Sewol ferry, and review of martial law during the Lee Myung-bak and Park Geun-hye governments came to light, about 80% of the public was found in polls to support abolishing the Gimu-sa or thoroughly reforming it. According to a RealMeter poll, 44.3% responded with thorough reform, 34.7% with abolition, 11.3% with maintaining the status quo, and 9.7% with "don't know." Even among supporters of the Liberty Korea Party, 41.7% responded with thorough reform, 6.3% with abolition, and 37.4% with maintaining the status quo, showing that opinion favoring thorough reform prevailed.8
Stalled investigation of secret leaks
The Defense Security Command detected that military secrets were being leaked by senior officers at the Navy Education Command by bypassing the military security program guards, and has been investigating for nearly a year. However, it has not found concrete evidence related to the leaks, and the investigation has run into difficulties. An insider filed a complaint again after retirement with the Anti-Corruption and Civil Rights Commission, a different government agency. Nevertheless, the investigation remained sluggish, and when the National Defense Committee's parliamentary audit opened in October 2014, the matter was placed on the official agenda and received serious criticism. For this reason, there are concerns both inside and outside the military that the sensitivity of the leaked material may be affecting the investigation.9
Concealment of internal sexual crimes
In July 2018, the Gimu-sa received a report from a female non-commissioned officer that she had been raped by a colleague. However, the Gimu-sa concluded that no rape had occurred and that it had been sexual intercourse by mutual agreement. The Military Human Rights Center and the female non-commissioned officer could not accept this, and reported to the Ministry of National Defense Investigation Headquarters, but no conclusion was reached, and the woman who claimed to be the victim retired.10
Manipulation of public opinion
Rep. Lee Chul-hee of the Democratic Party released a document that the Gimu-sa had reported to the Blue House on June 4, 2008, when the Lee Myung-bak government took office. In the document, after reviewing the status of "cyber personnel by agency," including the National Intelligence Service, the National Police Agency, the Joint Chiefs of Staff, and the Gimu-sa, the Gimu-sa proposed the operation of a non-public special team whose mission was "to respond to left-wing anti-government propaganda and agitation and to spread public opinion supporting the government." It also presented step-by-step activities: responding to left-leaning articles and columns, publicity through seminars, criticizing illegal activities of the left, and educating and organizing university students.11
In connection with the public opinion manipulation case, the Ministry of National Defense's General Court-Martial announced that it had issued an arrest warrant for a former Gimu-sa lieutenant colonel who is suspected of involvement in the Defense Security Command's public opinion manipulation activities and of publicly expressing political opinions.12
Activities related to the Sewol ferry disaster
During the Park Geun-hye administration, for six months immediately after the Sewol ferry disaster, the Gimu-sa compiled the personal information of the missing persons' families and representatives of the family support committee, classified their leanings, attempted to eradicate the families' "unreasonable demands" by conveying national criticism to them, and deployed Gimu activity officers to Paengmok Port and Danwon High School, reporting to it daily. In addition, the Gimu-sa provided conservative groups with documents on Sewol-related assembly information so that they could hold rallies to counter the assemblies held by civic groups.13
In September 2014, the Gimu-sa developed logic and methods to persuade the families of the missing to end the search, and the document states that this logic and these methods were "Blue House reporting items."14
The independent investigation team to examine the martial law allegations is expected to also investigate suspicions of surveillance of the Sewol ferry victims' families. Kim Eui-kyeom, spokesperson of the Blue House, said, "The President has instructed the independent investigation team to also investigate the suspicions of the Gimu-sa's surveillance of the Sewol victims' families."15
On August 2, the Ministry of National Defense Special Investigation Team (hereinafter the "Special Team") confirmed, from a USB drive related to the Gimu-sa's martial law documents, content on "preparations for implementing martial law" as well as the fact of surveillance of the Sewol victims' families. The Special Team stated, "After the Sewol disaster, the Gimu-sa formed a Sewol task force under the pretext of on-site support and, in addition to general support duties, carried out surveillance of the victims' families," and "we confirmed that through on-site and cyber surveillance, it collected and reported information on the families' leanings, their reactions to government announcements, photos of the families, educational backgrounds, and phone numbers."16
Review of martial law declaration against candle-light protests during the Park Geun-hye government
This was an incident in which, in connection with the impeachment trial of President Park Geun-hye, plans were prepared to issue garrison decrees and martial law in the event that the impeachment was dismissed or rejected. The Liberty Korea Party stated that these Gimu-sa actions were duties for contingencies, and took the position that "whether the Gimu-sa exceeded its authority should be examined, but if the military does not prepare to this extent in a situation where candle-light protest participants and Taegukgi rally participants are in confrontation, it is neglecting its duties."17 On the other hand, the government, the Democratic Party, the Bareunmirae Party, and the Justice Party are pursuing punishment of those involved in drafting the documents, searches of each unit, National Assembly hearings, as well as abolition of the garrison units established in metropolitan cities and provinces, demotion of the Gimu-sa commander's rank, and reduction of personnel.18
Chiefs of staff without command authority over counterintelligence units
The organization was subordinate to the Minister of National Defense and the President, and the chiefs of staff had no authority to command the Defense Security Command.19 Chun Doo-hwan, the first lieutenant who had drawn out the decisive clue for the success of the May 16 coup, was dispatched as personnel section chief to the creation of the Central Intelligence Agency,19 and President Park Chung-hee managed the military chain of command by dividing it into two systems: the official chain of command under the chief of staff and the intelligence system under the Defense Security Command commander.20
Due to the conflict between Chung Seung-hwa, the martial law commander and chief of staff, and the identity of Chun Doo-hwan and his subordinates, dissatisfaction arose over Chung Seung-hwa's personnel appointment of Major General Jang Tae-wan as commander of the Capital Garrison Command. This dissatisfaction was also conveyed to Kim Jong-pil, chairman of the Democratic Republican Party.21 Kim Jong-pil believed that the fact that dissatisfaction with military personnel had reached even the political sphere was a problem of control over the military from the official chain of command.21
Past commanders
Since 1991, the commander of the Gimu-sa has held protocol precedence among the three-star generals of the Republic of Korea Armed Forces immediately after the commander of the Republic of Korea Marine Corps, and ranks tenth among active-duty servicemembers.
Footnotes
Footnotes
“국군기무사령부령”. 《국가법령정보센터》. Ministry of Government Legislation, Republic of Korea. Accessed July 8, 2018. ↩