Dung, who joined the Viet Cong around 1961 when he would have been about 12, and served as a corpsman, then later led a surgery unit reportedly operating in the Delta's U Minh forest.

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During the Vietnam War, NVA and Viet Cong forces famously used the Ho Chi Minh Trail in Laos and Cambodia to attack the South, while U.S. forces were usually prohibited from chasing them back across the border.

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