98. Intelligence Memorandum1

No. 1620/66


The attack by uniformed North Korean troops on 2 November 1966 against a US patrol unit south of the Demilitarized Zone (DMZ) was apparently in retaliation for a South Korean (ROK) raid a week earlier. Although there has been a marked increase in North Korean harassing attacks along the DMZ since mid-October, these actions probably do not reflect a decision to engage in wholesale violations of the armistice agreement. The targeting of the 2 November raid against American troops suggests that Pyongyang was seeking to force the US to prevent any repetition of the raid on 26 October by some 30 ROK troops into the DMZ.
There is no evidence that the North Koreans intend to open a “second front” in the Vietnam War. However, it is possible that the North Koreans believe that heightened tensions along the DMZ would serve as a warning to the ROK and the US against further deployments of ROK troops to Vietnam and demonstrate North Korean support of Hanoi to other Communist states.
There is no indication that this upsurge of violence was related to President Johnson’s visit to South Korea. Recent interrogation of apprehended agents indicates these attacks had been planned long before the President’s Asian trip was announced.
Neither statements by North Korean leaders nor Pyongyang’s propaganda suggest an intention to divert US attention from Vietnam. Kim Il-song’s major policy statement on 5 October, although it made the customary offer to send “volunteers” to Vietnam, contained no threat to open a “second front” in Korea and the US commitment to Seoul probably remains an effective deterrent to such action.
South Korean military officials probably hoped that the ROK raid, which is claimed to have cost the enemy some 30 casualties and may have penetrated through the DMZ into North Korea, would boost morale lowered by North Korean incursions. Although the UN commander and the US ambassador have warned the South Koreans against repetition of such incidents, there is a danger that they will undertake carefully concealed reprisals if they suffer further personnel losses.
The North Korean presentation at the Military Armistice Committee meeting held on 4 November at Panmunjom followed the traditional propaganda pattern. The senior North Korean representative made no direct mention of the ROK raid, probably out of reluctance to call attention to North Korean vulnerabilities or to raise the question of North Korean casualties. He did accuse the UN side in general terms of numerous border violations.
The recent upsurge of violence by North Korean infiltrators suggests at least a temporary shift of mission from intelligence collection and subversion to harassment. In the past, infiltration agents—usually in civilian clothes—rarely engaged in fire-fights except when challenged by the ROK military or security services. Since mid-October, however, infiltration teams have deliberately sought out and attacked ROK forces. These probing operations may have been designed to test the effectiveness and reaction of South Korean forces deployed along the DMZ as well as to undermine troop morale.
North Korean agent operations along the DMZ have been conducted with varying intensity since the armistice agreement in 1953. In the past year, larger teams and more heavily armed operatives have been used. Agent teams began concentrated operations in the ROK last May. After the abnormal period of inactivity in September and early October probably caused by heavy rains and agent losses, North Korean infiltrators carried out seven surprise attacks against ROK troops in a five-day period beginning on 13 October. By 2 November, ROK and US forces had suffered some 36 fatalities (six US) in 40 incidents this year as compared with 20 Korean soldiers killed in 55 incidents in 1965 and four in 32 incidents during 1964.
The harassment along the DMZ is expected to taper off during the next few weeks as the foliage disappears and snow begins to fall. Normally, agent operations during the November–February period are infrequent because of bad weather.
  1. Source: Johnson Library, National Security File, Country File, Korea, Memos, Vol. III, November 1965 to December 1966. Secret; No Foreign Dissem/Background Use Only. Prepared by the Office of Current Intelligence of the Central Intelligence Agency and coordinated with the Office of National Estimates.