sentences:  The missions were originally controlled by the 2d Air Division until that headquarters was superseded by the Seventh Air Force on 1 April 1966.The geographic boundary of the operation was carved from the area of Laos already under bombardment under Operation Steel Tiger.This was done at the behest of the American commander in South Vietnam, General William C. Westmoreland, who saw the area of Laos that bordered the five northernmost provinces of South Vietnam as an extension of his area of operations.