In 1954 the CIA was engineering a "coup d'état" in Guatemala to replace its elected government with a dissident Guatemalan colonel, Carlos Castillo Armas. In May 1954 the Swedish cargo ship had evaded US sea and air patrols to deliver a cargo of Czechoslovak armaments to Puerto Barrios on Guatemala's Caribbean coast to augment the elected government's defences. The CIA was determined to prevent any further arms deliveries. This included using a covert "Liberation Air Force", disguised as rebels unconnected with the USA, that the CIA had created to support Colonel Castillo's few hundred rebels.