ST. LOUIS (AP) – Thirteen Muslims are suing U.S. immigration officials, alleging in the federal case filed in St. Louis a secret “blacklist” was slowing their quest for citizenship.

The Post-Dispatch reports that the lawsuit names U.S. Citizen and Immigration Services and immigration officials as defendants.

The suit alleges the Controlled Application Review and Resolution Program has flagged the immigrants as “national security concerns,” wrongly relying on such things as “innocuous activity and associations, innuendo, suppositions and characteristics such as national origin.”

The lawsuit alleges the program holds aspiring Muslim citizenship applicants to a higher legal standard and illegally bars them from upgrading their immigration status.

A USCIS spokesman says the agency “adjudicates all applications and petitions on a case-by-case basis according to existing laws, regulations, and USCIS policies.”