The Justice Department has filed a statement of interest in a NAACP lawsuit challenging North Carolina election boards that the civil rights group says are purging voters from voter rolls, and thereby violating the National Voting Rights Act.

The filing came late Tuesday ahead of an emergency hearing slated for Wednesday. The NAACP alleges that at least three counties have violated federal procedures and purged voter rolls based on undeliverable mail. The process disproportionately targets blacks, the NAACP argues.