With just over a week to go before Election Day, the North Carolina NAACP on Monday filed a lawsuit to stop what it describes as a Republican-led effort to snuff out the African-American vote.

“This is our Selma and we will not back down and allow this suppression to continue,” said Rev. William Barber II, president of the organization.

According to the civil rights organization, wrongful challenges to voters’ eligibility are happening in at least three counties—Beaufort, Moore, and Cumberland—and are disproportionately affecting African Americans.

The suit (pdf) states that “a small number of individuals have recently challenged the registration of approximately 4,500 voters, based exclusively on mass mailings that were returned as undeliverable.” A press statement from the group says the challenges stem from “a coordinated campaign led by individuals with GOP ties.” Registration cancellations based on that alone is in violation of the National Voting Registration Act, the group says.

The complaint, filed Monday in federal court in the Middle District of North Carolina, states, “in many cases, voters purged by Defendants still reside at the addresses where they are registered to vote, or have moved within the county and remain eligible to vote there.”

The suit is asking for the wrongfully canceled voting registrations to be restored.

Among the plaintiffs is James Edward Arthur Sr., who’s lived in Beaufort County his entire life. He is African American and has been a registered voter for five years. He was among the over 130 voters in that county to have his registration cancelled based on the challenge of an undeliverable mass mailing—even though he moved within the county.

“I did not receive notice from the State or Beaufort County that my voter registration had been challenged, or that a hearing had been set to determine whether I would remain on the State’s list of eligible voters,” he said, referring to the procedure that election officials must follow when a challenge has been made.