USS Pueblo Incident

January 5, 1968. USS Pueblo leaves the US Navy base in Yokosuka, Japan. Its destiny is the Democratic People's Republic of Korea (DPRK), commonly known as North Korea. USS Pueblo, designated AGER-2 (Auxiliary General Environmental Research), is a so-called technical research ship for oceanographic survey.

USS Pueblo AGER-2 in 1967 (source: US Navy)

In reality, the vessel is stuffed with SIGINT (Signals Intelligence) and ELINT (Electronic Intelligence) equipment. Its real mission is a joint Navy/NSA spy program to eavesdrop on North Korean and Soviet communications.

The Secret Mission Detected

January 20. USS Pueblo is observed a first time by a North Korean submarine chaser at 16 miles from the North Korean coast. Two days later, two fishing trawlers pass by at very close distance of USS Pueblo. The visitor is sighted and events start to enroll. The next day, January 23, USS Pueblo is approached by a DPRK sub chaser and, according to the US Navy, is challenged to show her nationality. After raising the U.S. flag, USS Pueblo is ordered to stand down or be fired upon.

According to the North Koreans, USS Pueblo is well inside their territorial waters. The U.S. version of the incident locates the spy ship far outside North Korean territory, but the North Koreans claim 50 nautical miles territorial waters, where international standards are 12 nautical miles. Whatever its position, USS Pueblo is in serious trouble. She desperately attempts to maneuver away from the much faster DPRK sub chaser, which is joined shortly after by four torpedo boats and another sub chaser. Two MIG-21 fighter jets fly over.

Damage Contol and Capture

For more than two hours, the DPRK vessels attempt to board USS Pueblo and repeatedly order the vessel to halt or be fired upon. The spy ship constantly manoeuvres to avoid the boarding but the cat and mouse game ends when one sub chaser opens fire with its 57 mm cannon on Pueblo's deck, wounding several crew members. USS Pueblo also receives machine gun fire from other DPRK vessels. Not equipped to respond to a serious threat (only .50 caliber machine guns are aboard, but covered to avoid suspicion and thus unmanned) USS Pueblo has no other option than to comply.

During the incident, USS Pueblo has continuous radio contact with the U.S. Naval Security Group in Japan, but air support is not be available on time. Meanwhile, below deck, intelligence personnel start destroying all sensitive documents and equipment. Normally, such spy ship, operating alone and close to enemy waters without protection, should carry only the absolute minimum of sensitive material. USS Pueblo, however, is loaded with documents and equipment. After an hour of emergency destruction, only a small percentage of the classified material aboard the ship is destroyed. An intelligence disaster is inevitable.

USS Pueblo is forced to follow the DPRK vessels but is fired upon again when she stops just outside North Korean territorial waters, killing one crew member and wounding several others. North Korean personnel now boards the vessel and takes over control. USS Pueblo is taken to Wonsan Naval Base, in southeastern North Korea. The Pueblo crew is moved to prisoner of war camps where, according to the crew, they are starved and regularly tortured while in North Korean custody.

SIGINT Fallout and Release of Crew

The capture of USS Pueblo was an intelligence nightmare. North Korea and its ally, the Soviets, seized large volumes of sensitive documents and cryptographic equipment, causing shock waves throughout the naval security and intelligence community.

Eleven months later, and only after a written apology and admission by the U.S. that USS Pueblo had been spying, its crew was released. On December 23, 1968, the 82 crew members crossed the DMZ border with South Korea (after the release, the U.S. immediately verbally retracted the ransom admission). The story however did not end with the release of the prisoners.

The captured USS Pueblo today in Pyongyang on the Botong river (source: laika ac)

Since then, USS Pueblo remained in the custody of North Korea. In 1999, the vessel moved from Wonsan to the North Korean capital Pyongyang, where it is now a primary tourist attraction on the Botong river, alongside the Victorious Fatherland Liberation War Museum. USS Pueblo AGER-2 is the only American naval vessel held in captivity in the world.

More information on USS Pueblo and its history is found on the beautiful USS Pueblo website (archived) and on the Naval History and Heritage Command. Many pictures from a visit to Pyongyang are available on Brian McMorrow's USS Pueblo photo gallery. The Wilson Center published A Reckless Act: The 1968 Pueblo Crisis and North Korea’s Relations with the Third World.

The Damage Documented

The USS Pueblo incident was one of the most catastrophic events to have damaged the codebreaking efforts of the National Security Agency (NSA). They released several historical papers on USS Pueblo, including the Cryptographic Damage Assessment. Robert Newton's paper on USS Pueblo is also available on their website.

The National Security Archive's The Secret Sentry Declassified published two documents related to the incident: The Capture of the USS Pueblo and Its Effect on SIGINT Operations (pdf-document 3) and some of the captured documents, from a North Korean expose on the ship’s mission (pdf-document 24).

 

KW-7 teletype encryption
(source: Jerry Proc)

The TSEC/KW-7 and the KL-47 (Navy version KL-7) were two of the crypto systems, compromised in the incident. Until today, the question remains whether the capture of USS Pueblo was a coincidence or that is was triggered by naval communications specialist John Walker and his spy ring. It is questionable whether the SIGINT and crypto equipment was indeed a planned target, since the North Koreans took that long before boarding the vessel, giving the crew the chance to destroy documents and equipment. More on the ship's electronics at Jerry Proc's USS Pueblo page.

USS Pueblo, John Walker and KGB (pdf) by Robert Derenčin is a detailed overview of Walker's spying and the damage he caused. See also the interview with KGB General Boris Solomatin.  

A Risky Job

 

Such SIGINT and ELINT missions have always been hazardous, even in peacetime. The Cold War was all but cold for the many intelligence technicians, sailors and pilots who lost their lives while collecting intelligence.

During an Israeli raid on USS Liberty AGTR-5, 34 crew were killed and and 173 wounded. Many SIGINT airplanes also got their share in the losses. The EC-121 #135749 (VQ-1) shootdown over the Sea of Japan in 1969 (all 31 killed) and the C-130A-II #60528 shootdown over Armenia in 1958 (all 17 killed) are only two of more than 40 reconnaissance aircraft that were shot down. NSA's National Vigilance Park has published a paper called A Dangerous Business: The U.S. Navy and National Reconnaissance During the Cold War.