10 years after becoming operational, the B-52 bomber saw action when 27 B-52F's from Andersen AFB, Guam, hit Vietcong strongholds in South Vietnam on June 18, 1965. This campaign known as Operation Arc Light had by year's end involved flying more than 1,500 sorties in South Vietnam, raining tons of bombs on enemy troop concentrations, bases and supply dumps. Laotian raids followed in December 1965, with raids to North Vietnam added in April 1966.