We’ll have more on this topic in future, based on our archive of declassified Pentagon and CIA reports on US infiltration of North Korea during and after the war (TLDR: The operations usually ended in failure, including the capture of a US Army intelligence officer who has never been returned or accounted for by Pyongyang. Penetrating North Korea, which constantly prepares to thwart such operations, is certainly one of the most difficult missions possible for US special operators.
The issue of US clandestine military operations against North Korea has come to the fore with a New York Times report on an ill-fated 2019 special operations mission on North Korean territory. “A group of Navy SEALs secretly entered North Korea in early 2019 to plant a device to intercept the communications of dictator Kim Jong Un — but ended up firing on unarmed civilians diving for shellfish, puncturing their lungs to conceal their bodies and aborting the mission, according to a New York Times report,” summarizes the NY Post (NYTimes story is paywalled.)
The bottom line: Infiltrating North Korea via the ocean (or land and air) is extraordinarily difficult. The country has built a surveillance state with strong emphasis on preventing such penetrations. Local villagers and fishermen are ordered to be watchful for enemy infiltrators and report them at once. Pyongyang also takes many other measures to protect its coast. In past, US intelligence has indicated that North Korea laid barriers of large fish hooks in areas where divers might attempt to land. In South Korea, soldiers raked the sand of vulnerable beaches to show the footprints of infiltrations — a tactic no doubt emulated in the North. Meantime, surveillance technology has dramatically improved, providing additional means to detect infiltrators. [It’s also not easy to infiltrate South Korea via the sea, which North Korea has done many times since the end of the war. In 1996 a North Korean special operations submarine ran aground off a South Korean beach, leading to the deaths of numerous North Korean operators (many killed by their own team) and a massive manhunt across South Korea.]
We’ve been researching for years US and South Korean operations against North Korea, and North Korean special operations against South Korea and US facilities. This includes substantial use of the Freedom of Information Act and research in the National Archives concerning the history of the Korean Demilitarized Zone (DMZ) and US/North Korean military engagements there and across the Korean area of operations, along with the fate of US POWs captured by the communists during the Korean War but never returned or accounted for. Many files from the mid-1950s onward remain classified, but there’s reason to believe the defenses America and South Korea had to penetrate in previous decades are even more substantial now.
Note: The author of this post brings a useful perspective on these issues. He led US operations against North Korean infiltrators in the Korean DMZ during the 1980s, was trained in special forces underwater operations and infiltration, and studied Korean history and language. He has also visited and conducted research in North Korea.
Failures of US Infiltrations of North Korea: Capture of US Army Officer on Mission
Previously classified files covering the 1950s demonstrate the challenges of US and South Korean covert operations in North Korea and other still-secret records no doubt hold more details. Some 10,000 South Korean agents infiltrated the North from the latter stages of the Korean War until 1972 (some accounts giving a later end date); about 8,000 never returned. This is based on RoK government statements and testimonials of South Korean agents who managed to return alive from North Korea.
Our research has also provided details on a US Army intelligence officer captured during a sea-borne infiltration of North Korea near the end of the Korean War.
CIA Files on Maritime Operations Against North Korea
The difficulty of martime operations against North Korea was proven during the Korean War. Declassified analysis of joint CIA and US military operations to insert and resupply agents in North Korea during and after the war found them generally unsuccessful, leading to the deaths of significant numbers of Korean agents working for the US, plus the capture of US Army intelligence officer Leonard Button (see below.)
The bottom line: Once the communist regime consolidated its control of North Korea during the latter years of the war and after, penetration missions became increasingly difficult. Inserting agents was highly dangerous and they were usually killed, or captured and doubled, not long after the landings. Aerial missions had similar problems and land infiltration was generally effective only within a few miles of the Demilitarized Zone/front lines.
Excerpt from “CIA in Korea, 1946-65 — Vol. 1”
Months after Pyongyang’s 1950 invasion of the South (with substantial help from the Soviets and communist Chinese), US and South Korean forces conducted a bold amphibious operation. The Inchon Landing was designed to cut off communist forces. Seaborne intelligence and commando operations behind enemy lines helped make the landing a success. But after the front lines stabilized later in the war, operations against North Korean-controlled territory became increasingly difficult. In the second year of the war, American maritime penetrations of North Korea supported by the Navy’s Underwater Demolition Team/UDT, precursor unit to the SEALS, proved successful for some limited objectives, according to a partially declassified CIA history.
But most other infiltration operations, often involving insertions of South Korean agents trained by the US, failed. A CIA history of operations against North Korea from 1946 to 1965, partially declassified, concludes that agent infiltrations, many maritime, during and right after the war, were a failure.
Some CIA Info That Remains Unavailable
| LT Leonard Button was a short but sturdy Baptist from Arkansas. The night of May 13, 1953, no doubt required all the strength his faith, Army training and WWII experiences could provide. What happened after that night may have been too much for even the strongest and most faithful man. While landing behind enemy lines in North Korea for a “highly classified intelligence mission,” Button’s team was discovered. Forced back from the shore by mortar fire, the infiltration boat could only listen to the small arms fire and grenade explosions from Button’s direction. Button, assigned to the 8240th Army Unit (see more below), was soon declared missing in action. [See more information on Button’s capture below.] The next year, an Army general wrote his family (see document below), saying: “Since your son, First Lieutenant Leonard W. Button…was reported missing in action on 13 May 1953, the Department of the Army has entertained the hope that he survived and that information would be received dispelling the uncertainty regarding his absence. However, as in many cases, no information has been received to clarify his status. …In view of the lapse of time without information to support a continued presumption of survival the Department of the Army must terminate such absence by a presumptive finding of death.” The letter added: “I regret the necessity for this message but hope that the ending of a long period of uncertainty may give at least some small measure of consolation.” What the Army did not tell his family in 1954, and may never have told them, is that Leonard Button was known to have been captured alive on the night of May 13, 1953, along with Koreans on his mission. According to previously Top Secret Army documents (see below) obtained from the US military under the Freedom of Information Act, “Lt. Button was seen and identified alive on 21 May 1953 and further was reportedly tried and sentenced by the (North Korean) Ministry of Social Security…” Army intelligence listed Button among “US personnel known to have been alive and under communist control in May 1953.” However, Button was never returned or accounted for in the US prisoner exchanges with North Korea and its communist Chinese ally after the war ended in July 1953. The Pentagon continued to list Button as an MIA, despite its Top Secret records showing he had been captured alive, imprisoned, sentenced and never returned by the enemy. Then, during the 1990s, the Russian government confirmed Button’s survival from its own records. Button was captured by the “5th Army of North Korea’s counterintelligence organs. He was captured during the period when he went to meet his two agents who wever coming back from a mission…This information was given to us by the North Koreans…” Given that both American intelligence (reviewed by the Pentagon POW office during the 1990s) and Russia confirmed Button was a POW, not MIA, what has the Pentagon done about his case? Apparently not much: 1LT Leonard Button was still listed as MIA (nor POW) by the Pentagon until recent years. The Pentagon now lists Button as “unaccounted for” and has released additional information on his maritime operation and capture: “First Lieutenant Leonard Wayne Button, who joined the U.S. Army from Arkansas, served with the 8240th Army Unit, Far East Liaison Detachment, Korea. On May 14, 1953, 1LT Button, who was based on Kodo Island, Wonsan Harbor, approached the North Korean shoreline in a small boat for a pre-arranged meeting with undercover agents. North Korean soldiers were waiting for him. He tried to escape by diving off the boat and swimming away, but he was captured and imprisoned. He was last seen entering a prison near Pyongyang under heavy escort. He was not officially reported to be a prisoner of war, and his remains have not been identified among those returned to U.S. custody,” the Pentagon says today. Notes: the 8240th Army Unit was a US special operations organization that managed guerrilla and intelligence operations behind enemy lines. It is linked to several other important POW cases, including the incredible case of the “Ashley Five,” a group of American aviators known to have been alive in North Korean captivity at the very end of the Korean War but never returned (their fate too hidden behind Pentagon secrecy for decades); two missing American soldiers from related units (Sgt. George Tatarakis and SFC William Miles) reported to have been captured and sent to the Soviet Union; and more recently the 2013 detention of Merrill Newman, a veteran of the 8240th who was detained by Pyongyang when he visited North Korea as a tourist 60 years after the war. We believe the North Koreans and their Soviet advisors focused on capturing Americans involved in operations behind the lines in North Korea and likely decided to keep some of them back at the end of the war due to their intelligence value. [See more information on US soldiers held by North Korean, Chinese and Soviet forces but never returned or accounted for at the non-profit POW Investigative Project, a multilingual crowdsourcing site that seeks answers on American soldiers reported alive in North Korea years after the war, US aviators known in North Korean hands at the end of the Korean War bur never returned, and other Korean, Cold and Vietnam War cases.] |
Documents declassified in recent years (including the one below from an ongoing lawsuit by POW/MIA family members and the publisher of this site), reveal post-war agent insertions in North Korea by US Army intelligence. The operations became increasingly difficult in the summer of 1954 due to increased North Korean naval patrols: “This added security provided further deterrents to agent operations in this area.” The documents also reveal that RoK intelligence, and even in one case US Army counterintelligence personnel, impeded Army intelligence efforts to recruit and train South Korean civilians for operations in the North and “stay-behind” missions in South Korea, for use if North Korea overran part of the country.
US Army Officer Captured During Landing Behind North Korean Lines Near End of the Korean War (He Was Never Returned)
Information on Lt. Button’s Capture Provided by Moscow
Previously Classified US Intel Report on Button’s Capture
