Prior to 1965, the base at U-Tapao was a small RTN airfield. At Don Muang Air Base near Bangkok, the USAF had stationed KC-135 tanker aircraft to refuel combat aircraft over the skies of Indochina. Although Thailand was an active participant in the Vietnam War, with a token ground force deployed to the South Vietnam as well as involved in the largely secret civil war in Laos, the presence and the visibility of USAF aircraft near its capital city was causing a fair degree of political embarrassment for Thailand's military government.