Camps administered by the Justice Department for the detention of enemy aliens (not U.S. citizens) deemed dangerous during World War II. Most of the several thousand people in these camps were Issei and Kibei who had been rounded up after the attack on Pearl Harbor because they were perceived as "dangerous." "Internment camp" is used by some to describe the "incarceration camps." The term "internment" is problematic when applied to U.S. citizens. Technically, internment refers to the detention of enemy aliens during time of war, and two-thirds of the Japanese Americans incarcerated were U.S. citizens.