USS Pueblo on a trip to sea.

In the 1970s, the US Navy was keen to gather intelligence on North Korean submarines, as well as advanced Soviet submarines believed to be operating in the area.

According to declassified documents from the National Security Archive, the vehicle chosen by US intelligence was the spy ship USS Pueblo (AGER-2) equipped with many modern technologies to collect information from the North Korean military.

In January 1968, the USS Pueblo departed from the military port of Sasebo, Japan under the guise of a scientific research ship to Korean waters to perform its mission.

On January 23, 1968, USS Pueblo conducted reconnaissance operations off the coast of Wonsan, North Korea’s largest military and logistics port.

`We didn’t have any weapons to fight back because at that time our ship was in disguise and didn’t carry weapons,` Skip Schumacher, an officer on the ship at the time, recalled.

Captain USS Pueblo tried to buy time by steering the ship out to sea.

Within just an hour, one American sailor was killed and many were injured by North Korean fire.

North Korea’s seizure of the USS Pueblo and much of the National Security Agency’s (NSA) equipment poses a major threat to US intelligence security, causing the administration of President Lyndon Johnson a headache in finding a way to respond.

Retaliatory measures include blockading North Korean seaports, air strikes on military targets, attacks along the border dividing the two Koreas, and displays of air and naval power outside Wonsan port, where USS

USS Pueblo is displayed in a museum in North Korea.

The seizure of the ship made the US very angry, but there was no intelligence information about the whereabouts of the sailors, so conducting a rescue operation was impossible.

President Lyndon Johnson and his advisors sought to free them without causing a second Korean War, causing China and the Soviet Union to enter the war.

The negotiation process has begun.

82 American sailors were escorted across the bridge at Panmunjon to Korea and returned to the United States on Christmas of the same year.

The USS Pueblo is still in the US Navy today.

`The 326-page secret document on the NSA’s USS Pueblo incident in 1992 shows that this seizure is considered one of the biggest failures in the history of US intelligence,` said historian Jack Cheevers.

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