A lawsuit was filed against Alabama Secretary of State Wes Allen, a Republican, on Friday alleging he attempted to remove 3,251 people registered to vote from the state’s rolls. Allen said on Monday it was his “constitutional duty to ensure that only American citizens vote in our elections” but did not elaborate further, citing the lawsuit filed in the U.S. District Court for the Northern District of Alabama.

Right-leaning groups such as America First Legal Foundation, founded by former Trump administration adviser Stephen Miller, accused the Biden administration of trying to “keep illegals on voter rolls.”

“The Biden-Harris DOJ sued the State of Alabama for fighting to remove potential noncitizens and illegal aliens from their voter rolls ahead of the 2024 election,” AFL’s account posted to X on Saturday.

The move by Allen aimed to remove people from voter rolls who were issued noncitizen identification numbers by the Department of Homeland Security, but the federal government contends some native-born and naturalized citizens were caught in the purge.

“The Justice Department’s review found that both native-born and naturalized U.S. citizens have received letters stating that their voter record has been made inactive and that they have been placed on a path for removal from Alabama’s statewide voter registration list,” the DOJ wrote in a press release on Friday.

Allen is also accused of waiting too long to begin purging voters, as the program was announced on Aug. 13, under 90 days before the election. The DOJ said the move marked a violation of the “Quiet Period Provision” of the National Voter Registration Act.

A voting rights group separately sued Allen over the same decision to purge voter rolls on Sept. 13. U.S. District Judge Anna Manasco, an appointee of former President Donald Trump, combined the DOJ and voting rights group’s suits in an order on Saturday.

The DOJ is asking Alabama to send a notice to voters removed from the rolls, informing them they’ve been restored, can vote on Election Day, and won’t face criminal prosecution. It also asks for public information on halting and reversing the purge program, education for election officials about these changes, and any additional measures as required for justice.

Meanwhile, Allen has said he is committed to ensuring Alabama has the “cleanest” voter rolls in the country.

“I have been clear that I will not tolerate the participation of noncitizens in our elections,” Allen wrote in a press release about his voter roll purge initiative.

A virtual status conference for the case was scheduled for 2 p.m. on Monday, according to Manasco’s order on Saturday.