Voting rights groups filed a federal lawsuit Wednesday that accuses the Georgia secretary of state’s office of improperly removing nearly 200,000 people from the state’s voter registration list last year.

The lawsuit says the state removed tens of thousands of voters from the list because it believed they had moved away when, in fact, they had not. It also challenges a “use it or lose it” provision in state law that allows Georgia to purge voters who do not cast ballots for many years. That allowed the state to remove tens of thousands more voters, the lawsuit says.

The lawsuit was filed in U.S. District Court in Atlanta by the Black Voters Matter Fund, the Transformative Justice Coalition and the Rainbow Push Coalition.

Latosha Brown, a co-founder of the Black Voters Matter Fund, said at a press conference Wednesday announcing the lawsuit that the purge amounted to “massive-scale voter suppression.”

The secretary of state disputed the claim of a faulty voter purge when it first arose in September, and it did so again Wednesday. Gabriel Sterling, Georgia’s voter system manager, said the office follows federal rules for maintaining its voter registration list.

“Let’s not call it a purge,” Sterling said. “It’s federally mandated list maintenance.”

Georgia maintains a database of millions of registered voters. It must keep the list up to date to prevent anyone not eligible to vote in Georgia from casting a ballot. It removes voters from the list if they have died, moved away, been convicted of a felony or failed to vote or contact election officials for many years.

Last fall Georgia removed about 287,000 voters from the registration list. The lawsuit says nearly 200,000 of those people were improperly removed and seeks to have their registrations restored.

The lawsuit is based on a report released by the American Civil Liberties Union in September. At the time, the secretary of state’s office called it “misinformation” and demanded the group release its data or retract its report.