During the early years of World War II, Japanese Americans were forcibly relocated from their homes in the West Coast because military leaders and public opinion combined to fan unproven fears of sabotage. As the war progressed, many of the young Nisei, Japanese immigrants' children who were born with American citizenship, volunteered or were drafted to serve in the United States military. Japanese Americans served in all the branches of the United States Armed Forces, including the United States Merchant Marine. An estimated 33,000 Japanese Americans served in the U.S. military during World War II, of which 20,000 joined the Army. Approximately 800 were killed in action.