The U.S. Department of Justice on Tuesday sued Arizona in a bid to block a recently enacted law forcing residents to show proof of citizenship in order to vote in federal elections.

Assistant U.S. Attorney General for the Civil Rights Division Kristen Clarke said in a statement that the “onerous documentary proof of citizenship requirement” in the Arizona law, H.B. 2492, “constitutes a textbook violation of the National Voter Registration Act.”

As Common Dreams reported, voting rights advocates have sounded the alarm over the law, which is set to go into effect in January, and which People for the American Way warned could prompt “the most extreme voter purge in the country.”

According to one estimate, as many as 192,000 Arizonans could be stricken from the state’s voter rolls if the law takes effect.

In a press call, Clarke said that “Arizona is a repeat offender when it comes to attempts to make it harder to register to vote.”

“For nearly three decades, the National Voter Registration Act has helped to move states in the right direction by eliminating unnecessary requirements that have historically made it harder for eligible voters to access the registration rolls,” she continued. “Arizona has passed a law that turns the clock back on progress by imposing unlawful and unnecessary requirements that would block eligible voters from the registration rolls for certain federal elections.”

“This lawsuit reflects our deep commitment to using every available tool to protect all Americans’ right to vote,” Clarke added, “and to ensure that their voices are heard in our democracy.”