Pleiku on 7 February 1965, a series of airstrikes was initiated, Operation Flaming Dart, while Soviet Premier Alexei Kosygin was on a state visit to North Vietnam. Operation Rolling Thunder and Operation Arc Light expanded aerial bombardment and ground support operations. The bombing campaign, which ultimately lasted three years, was intended to force North Vietnam to cease its support for the Viet Cong by threatening to destroy North Vietnamese air defenses and industrial infrastructure. It was additionally aimed at bolstering the morale of the South Vietnamese. Between March 1965 and November 1968, Rolling Thunder deluged the north with a million tons of missiles, rockets and bombs. Bombing of Laos Bombing was not restricted to North Vietnam. Other aerial campaigns, such as Operation Barrel Roll, targeted different parts of the Viet Cong and PAVN infrastructure. These included the Ho Chi Minh trail supply route, which ran through Laos and Cambodia. The ostensibly neutral Laos had become the scene of a civil war, pitting the Laotian government backed by the US against the Pathet Lao and its North Vietnamese allies. Massive aerial bombardment against the Pathet Lao and PAVN forces were carried out by the US to prevent the collapse of the Royal central government, and to deny the use of the Ho Chi Minh Trail. Between 1964 and 1973, the U.S. dropped two million tons of bombs on Laos, nearly equal to the 2.1 million tons of bombs the U.S. dropped on Europe and Asia during all of World War II, making Laos the most heavily bombed country in history relative to the size of its population. The objective of stopping North Vietnam and the Viet Cong was never reached. The Chief of Staff of the United States Air Force Curtis LeMay, however, had long advocated saturation bombing in Vietnam and wrote of the communists that "we're going to bomb them back into the Stone Age". The 1964 offensive Following the Gulf of Tonkin Resolution, Hanoi anticipated the arrival of US troops and began expanding the Viet Cong, as well as sending increasing numbers of North Vietnamese personnel southwards. At this phase they were outfitting the Viet Cong forces and standardising their equipment with AK-47 rifles and other supplies, as well as forming the 9th Division. "From a strength of approximately 5,000 at the start of 1959 the Viet Cong's ranks grew to about 100,000 at the end of 1964... Between