Under the 1954 Geneva peace accords, reunification elections were to be held in Vietnam within two years. Prime Minister Diem rejected the election promise and took excessive steps to repress any opponents. The strategic hamlets were not welcome by the peasant population and by 1964, supplies were flowing south along the Ho Chi Minh trail. Viet Cong guerrillas supported the Army of North Vietnam (ARVN) attacked American installations in Saigon. The bombing of the North started in in 1965 in reaction to the Gulf of Tonkin incident. The Marines that began arriving in 1965 were not seen as liberators by the people. The North launched a major attack in 1965 on the airbase at Da Nang. It was eventually recognized that the bombing campaign, Operation Rolling Thunder, had failed.