NASHVILLE (AP) — Tennessee's top election office has sent letters to more than 14,000 registered voters asking them to prove their citizenship, a move that alarmed voting rights advocates as possible intimidation.

The letters, dated June 13, warned that it is illegal in Tennessee for noncitizens to vote and provided instructions on how to update voter information. The list was developed after comparing voter rolls with data from the state Department of Safety and Homeland Security, said Doug Kufner, spokesperson for the Secretary of State's office, in a statement Tuesday.

Kufner described the data from the state's homeland security department as a "snapshot" of a person's first interaction with that agency. Some may not have been U.S. citizens when they obtained a driver's license or ID card but have since been naturalized and "likely did not update their records," he said. Driver's licenses in Tennessee must be renewed every eight years.

"Accurate voter rolls are a vital component to ensuring election integrity, and Tennessee law makes it clear that only eligible voters are allowed to participate in Tennessee elections," Kufner said.

The letter does not, however, reveal what would happen to those who do not update their records — including whether people who fail to respond will be purged from the voter rolls. Kufner did not immediately respond to an email seeking clarity on if voters were at risk of being removed.

Instead, the letter contains warnings that illegal voting is a felony and carries penalties of up to two years in prison.

Voting rights advocates began raising the alarm after photos of the letter started circulating on social media. Democrats have long criticized the Secretary of State's office for its stances on voting issues in the Republican-dominant state.

"The fact legal citizens of the United States and residents of Tennessee are being accused of not being eligible to vote is an affront to democracy," said state Rep. Jason Powell, a Democrat from Nashville, in a statement. "These fine Tennesseans are being burdened with re-proving their own voter eligibility and threatened with imprisonment in a scare tactic reminiscent of Jim Crow laws."

Powell and fellow Democratic Rep. John Ray Clemmons on Tuesday urged Attorney General Jonathan Skrmetti to investigate the issue.

Democratic Rep. Gloria Johnson, a Democrat from Knoxville, said she was informed that one of the letter recipients included a "respected scientist in Oak Ridge" who had become a citizen and registered to vote in 2022.

"Maybe the state should verify citizenship with the federal government before sending threatening/intimidating letters to new citizens," Johnson posted on X, the platform formerly known as Twitter.

Other leaders encouraged those who received a letter to reach out to the American Civil Liberties Union of Tennessee for possible legal resources.

"It is surely capturing many, many, many eligible citizens on the rolls and threatening them with criminal prosecution," said Sean Morales-Doyle, director of the voting rights program at The Brennan Center for Justice at New York University's School of Law. "I think it's unconscionable. And I think that it likely violates a number of federal laws as well."

The effort bears some resemblance to the rollout of a sweeping Texas voting law passed in 2021, in which thousands of Texans — including some U.S. citizens — received letters saying they have been flagged as potential noncitizens who could be kicked off voting rolls.

Texas officials had just settled a lawsuit in 2019 after a prior search for ineligible voters flagged nearly 100,000 registered voters but wrongly captured naturalized citizens. A federal judge who halted the search the month after it began noted that only about 80 people to that point had been identified as potentially ineligible to vote.