In 1968 a North Korean black ops assassination team got within 100 metres of the South Korean president’s house. South Korea formed a team of petty criminals and teenagers to return the favour, but after three years of training they mutinied.
In 1966 tensions were high between North and South Korea. The armistice agreement that ended the Korean War had been breached by the United States, who had deployed nuclear weapons in South Korea against the explicit terms of that agreement (although they claimed that North Korea had broken it first). North Korea responded by starting plans for a black ops attack on the south.
Thirty-one officers from the North Korean army began training for a secret mission across the Korean DMZ and into South Korea. Their plan: assassinate the South Korean President Park Chung-hee. Park had seized power in a 1961 coup and idea was that his death would throw the south into disarray. The back ops team, known as Unit 124, was very nearly successful.
In January 1968, Unit 124 infiltrated the south in disguise. They got within 100 metres of Park’s Seoul residence, but were stopped and questioned at a police checkpoint. The police chief drew his gun, the North Korean troops shot him, and their secret was out. The whole team was killed (or killed themselves) with only two survivors. One was captured, held for a year, and eventually released; he lives in South Korea to this day. The other managed to get back to North Korea and is now a high ranking general and government minister.
The failure of the Unit 124 raid led to the creation of a South Korean black ops team. In contrast to the North Korean team, Unit 684 was formed by rounding up a ragtag crew of petty criminals and disaffected teenagers, dropping them on an uninhabited island, and beginning military training. For the next three years they trained for an incursion into North Korea to assassinate its leader Kim Il-sung.
The Unit 684 incursion never happened. Relations between north and south thawed considerably, and the assassination mission was cancelled. Concerned that they would never be allowed to leave the island, Unit 684 mutinied, killed their guards, and fled to Seoul on a hijacked bus. They were caught and killed (or killed themselves). Four of the black ops team survived, only to be tried and executed the next year.