Saigon fell to the North Vietnamese army supported by Viet Cong units on April 30, 1975. Schlesinger had announced early in the morning of April 29 the beginning of Operation Frequent Wind, which entailed the evacuation of the last U.S. diplomatic, military and civilian personnel from Saigon via helicopter, which was completed in the early morning hours of April 30. Not only did North Vietnam conquer South Vietnam, but the communists were also victorious in Cambodia when the Khmer Rouge captured Phnom Penh on April 17, as were the Pathet Lao in Laos successful in capturing Vientiane on December 2. Like Saigon, U.S. civilian and military personnel were evacuated from Phnom Penh, U.S. diplomatic presence in Vientiane was significantly downgraded, and the number of remaining U.S. personnel was severely reduced.