Within hours of the news from Hawaii, FBI agents, many without evidence, search or arrest warrants, conducted house to house roundups of 1,212 Issei (first-generation Japanese immigrants) in Hawaii and the mainlandThey were prominent leaders in the Japanese-American communities: priests, teachers in language schools, officers of community organizations, and newspaper editors. Often they were arrested in the middle of the night, taken to unknown destinations, and treated as prisoners of war.
Subsequently, many Issei leaders were placed into U.S. Justice Department internment camps in New Mexico, North Dakota, Texas, and Montana. Some were paroled to their families after receiving clearance from an Enemy Alien Hearing Board.
In the days that followed, presidential proclamations declared various restrictions on German, Italian, and Japanese residents in the U.S. All nationals and subjects of Axis countries were identified as “enemy alien.”
The Nisei (second-generation, U.S.-born children of the Issei) who were American citizens by birth, were designated as “non-aliens” and were subjected to the same restrictions. Their travel, work hours, and social gatherings were severely restricted and their contraband articles confiscated. Those deemed “dangerous to the public peace or safety of the U.S.” were subject to apprehension.
In the months that followed, these restrictions on travel and the possession of contraband items were placed upon aliens from Japan with increasing severity, while they were substantially relaxed for German and Italian aliens.