sentences:  At the time, the CIA had been training Montagnard tribesmen under the Village Defense Program (later to become the Civilian Irregular Defense Group) with the stated intention of resisting communist infiltration, but Đính regarded it was an attempt to divide and conquer and undermine him.He estimated that 18,000 tribesmen had been armed, and said to Ngô Đình Nhu – one of Diệm's younger brothers and his chief adviser – that "the Americans have put an army at my back".CIA officer Lucien Conein admitted years afterwards that Đính's claim was correct; that Nhu and Diệm had no previous idea of what the Americans had been doing.