Everything changed during World War II, when India became the main base for the American China Burma India Theater (CBI) in the war against Japan. Tens of thousands of American servicemen arrived, bringing all sorts of advanced technology, and money; they left in 1945. Serious tension erupted over American demands, led by US President Franklin D. Roosevelt, that India be given independence, a proposition Churchill vehemently rejected. For years, Roosevelt had encouraged British disengagement from India. The American position was based on an opposition to Europeans having colonies and a practical concern for the outcome of the war, and the expectation of a large American role in a post-independence era. However, in 1942 when the Indian National Congress launched a Quit India Movement, the colonial authorities arrested tens of thousands of activists. Churchill threatened to resign if Roosevelt continued to push his case, so Roosevelt backed down. Meanwhile, India became the main American staging base to fly aid to China. During World War II, the Panagarh Airport in the state of West Bengal in India was used as a supply transport airfield from 1942-1945 by the United States Army Air Forces Tenth Air Force and as a repair and maintenance depot for B-24 Liberator heavy bombers by Air Technical Service Command.