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 infiltration 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..., agents attempted unsuccessfully to assassinate President Park... Subsequently, P'yongyang's infiltration efforts abated somewhat, and the emphasis shifted back to intelligence gathering and covert networks.
During the late 1960s, the North had significantly escalated its subversion and infiltration activities against the South--from about 50 incidents in 1966 to more than 500 in 1967. One of its most brazen acts was an attempt in January 1968 by North Korean commandos, who penetrated to within a mile of the presidential palace, to kill South Korean President Park Chung Hee. In the climate of improved East-West relations in the early 1970s, the North called off its insurgency campaign, and talks between the North and South began at P'anmunjom in September 1971.
On 18 January 1968, 31 North Korean commandos, disguised as South Korean soldiers and civilians, crossed the demilitarized zone (DMZ) between the two countries and headed for Seoul with the intention of assassinating President Park Chung Hee. They reached the capital on 21 January but were intercepted by police, and a gun battle broke out, during which five of the commandos, one South Korean policeman and five civilians were killed. Some of the commandos were later killed in a fire-fight with American troops as they tried to escape back across the DMZ, and the commander of the operation was captured and admitted that his object hadbee the president.