As a part of the war in Vietnam, the United States military sprayed millions of gallons of herbicides and defoliants between 1962 and 1971 under Operation Ranch Hand. Agent Orange was commonly used to strip the Viet Cong guerrillas of forest cover and food sources, killing trees and crops. US government records from Operation Ranch Hand show that Cambodia was also targeted with Agent Orange in Svay Rieng province, where an herbicide spraying mission crossed over the border from Vietnam. Little is known about the use of Agent Orange in Cambodia, but the people in Svay Rieng's Koki Som commune recalled seeing the planes and still feel the effects of a possibly undocumented US mission in 1970.