Beginning in 1950, US military advisers arrived in what was then French Indochina. After World War II, Vietnam was divided into communist North Vietnam, supported by the Soviet Union and China, and South Vietnam, supported by the United States, South Korea, Australia, and other anti-communist allies. The Viet Cong, South Vietnamese communist guerrillas, aided by large numbers of communist North Vietnamese, fought against South Vietnamese and United States forces. United States involvement escalated after the 1964 Gulf of Tonkin incident, when a US Navy destroyer was attacked by a North Vietnamese war ship, and the Gulf of Tonkin Resolution authorized the US President to increase the United States military presence. United States combat units were deployed in 1965. As the war raged, military operations crossed international borders, and Laos and Cambodia also became involved. American involvement peaked in 1968, the same year the communists launched the Tet Offensive. Although the Tet Offensive failed, it became the turning point of the war by persuading a segment of the US population that progress in winning the war was lacking despite massive US military aid to the South Vietnamese. Gradual withdrawal of US forces began during Vietnamization, which aimed to end US involvement in the war. Despite the Paris Peace Accord signed in January 1973, the fighting continued. US involvement ended on 15 August 1973. The capture of Saigon by the North Vietnamese on 30 April 1975 ended the war. United States casualties were 58,315 dead and 303,644 wounded. Returning US Vietnam veterans were neglected, ignored, disrespected, suffered abuse and insults, were spit upon, and worse.