After the division of the peninsula, North Korea used subversion and sabotage against South Korea as part of its effort to achieve reunification. North Korea was unsuccessful at developing a covert political infrastructure in South Korea or forging links with dissidents resident in South Korea, and after the early 1960s P'yongyang's efforts were unproductive. Based on available evidence, in 1990 it appeared that P'yongyang placed or recruited only a limited number of political agents and sympathizers in the southern part of the peninsula. P'yongyang's agents acted individually for the most part, did not maintain regular contact with one another, and received only intermittent support and guidance.
Peacetime infiltration by North Korean agents was a fact of life in South Korea after the armistice in 1953. There were, however, clear shifts both in the number and method of infiltrations over the years and in their goals. Through the mid1960s , P'yongyang sent agents primarily to gather intelligence and to try to build a covert political apparatus. This tactic was followed by a dramatic shift to violent attempts to destabilize South Korea, including commando raids along the DMZ that occasionally escalated into firefights involving artillery. These raids peaked in 1968, when more than 600 infiltrations were reported, including an unsuccessful attempt at a commando attack on the Blue House in Seoul and the infiltration of over 120 commandos on the east coast. In 1969 more than 150 infiltrations were attempted, involving almost 400 agents. In 1970 and 1974, agents attempted unsuccessfully to assassinate President Park. In the 1974 attempt, during an August 15 ceremony marking National Liberation Day at the National Theater in Seoul, the assassin's shots missed President Park but killed Mrs. Park. Subsequently, P'yongyang's infiltration efforts abated somewhat, and the emphasis shifted back to intelligence gathering and covert networks.
From the mid-1970s to the early 1980s, most North Korean infiltration was done by heavily armed reconnaissance teams, which increasingly were intercepted and neutralized by South Korean security forces. After shifting to infiltration by sea for a brief period in the 1980s, P'yongyang apparently discarded military reconnaissance in favor of inserting agents from third countries. North Korea did not abandon violence, however, as was shown by the abortive 1982 attempt to recruit Canadian criminals to assassinate President Chun Doo Hwan, the 1983 Rangoon assassination attempt that killed seventeen South Korean government officials and four Burmese dignitaries, and the 1987 destruction of a Korean Air airliner with 115 people on board. In the airliner bombing, North Korea broke from its pattern of targeting South Korean government officials, in particular the president, and targeted ordinary citizens.
North Korean propaganda concentrated on weakening the social fabric and sowing discord between the South Korean government and the population. Indirectly, North Korea sought to turn dissident elements within South Korean society into propagandists and agitators who would undermine the government. P'yongyang achieved some limited indirect success in this effort, as indicated by the repetition of some of its themes by student dissidents. North Korean coverage of dissident activity in the south was on occasion so timely and accurate as to lead some members of the South Korean government to believe that dissent in the south was directed from the north. However, despite similarities between North Korean propaganda and dissident statements, South Korean security agencies never convincingly established a direct connection between the dissidents and the north, although in the late 1980s some elements among dissident groups increasingly used Marxist-Leninist language and North Korean political themes (see Political Extremism and Political Violence , ch. 4).
Data as of June 1990