Taking advantage of the situation, Thailand launched the Franco-Thai War in October 1940. Japan stepped in as a mediator in the war in May 1941 and allowed its ally to occupy the bordering provinces in Cambodia and Laos. In July 1941, as Operation Barbarossa had effectively neutralised the Soviet threat, the faction of the Japanese military junta supporting the "Southern Strategy" pushed through the occupation of the rest of French Indochina.