Page "History of North Korea" Paragraph 16

Meanwhile, the peninsula remained divided and relations with the ROK and the United States were bitterly hostile.

But when the US became engaged in Vietnam around this time, Kim saw an opportunity.

Inspired by the actions of the Vietcong, he began employing his own guerrilla squads to infiltrate South Korea, spread propaganda, and commit sabotage.

North Korean agents came south in 1966-1969, creating disruption, but ultimately failing to win over the South Korean populace.

Actions such as an attempted assassination of ROK president Park Chung-Hee in Seoul failed, and Kim publicly disclaimed any responsibility for them.

North Korean fighter pilots were also sent to Hanoi's assistance ( and conversely South Korea sent a contingent of troops to aid the government in Saigon ).