It was not immediately clear how many immigrants have been reviewed under the program, which began in 2008 and is formally known as the Controlled Application Review and Resolution Program.
The ACLU learned about the program through records requests after detecting a pattern in cases of Muslim immigrants whose applications to become American citizens had languished.
A government program to screen immigrants for national security concerns has blacklisted some Muslims and put their U.S. citizenship applications on hold for years, civil liberties advocates said Wednesday.
The American Civil Liberties Union of Southern California said in a report that the previously undisclosed program instructs federal immigration officers to find ways to deny applications that have been deemed a national security concern. For example, they flag discrepancies in a petition or claim they didn’t receive sufficient information from the immigrant.