1968년 2월 20일 미국의 Cyrus Vance 특사가 (1964~1967년 국방차관, 1977~1980년 국무장관) 린든 존슨 대통령에게 보고한 내용인데 당시 북한의 무장공비 침투에 대응해서 우리도 특수부대를 침투시켰고, Vance의 방문 전 몇 달은 1달에 평균 2번 침투했으며, 1967년 11월에는 12명으로 이루어진 특수부대가 북한군 사단본부를 폭파시키고 피해 없이 돌아왔다고 합니다.

http://history.state.gov/historicaldocuments/frus1964-68v29p1/d181

181. Memorandum From Cyrus R. Vance to President Johnson¹

Washington, February 20, 1968.

The Objectives of My Mission

Under the broad delegation of authority given me, I formulated the specific objectives of my Mission in the following terms:

“The objective of my Mission is to persuade President Park, and through him the Korean Government, that we intend to stand firmly with them in the current crisis and that our policy for handling the developing situation is soundly based.

(중략)

With one significant exception, we placed the onus on them to raise topics for discussion. The exception concerned South Korean forays across the DMZ into the North. This information was news to most members of the Cabinet since the South Korean infiltration units are under the personal control of Minister of National Defense Kim and their activities are closely held secrets within the ROKG. We emphasized the provocative nature of these attacks, which, over the past several months, have averaged two per month. We suggested that some of the more serious North Korean incursions into the South may have been launched in retaliation for South Korean raids, in particular the November 1967 raid against a North Korean Peoples Army Divisional Headquarters. The Headquarters was apparently blown up and the twelve-man South Korean strike team exfiltrated without sustaining any casualties. We pointed out that there was no evidence that the South Korean forays had had a chastening effect on Kim Il-Sung.