The Texas Secretary of State says nearly 100,000 people on the state's voter rolls are not U.S. citizens.

In an advisory today, Secretary of State David Whitley told voter registrars that the Texas Department of Public Safety has identified as many as 95,000 non-U.S. citizens who have a registration record attached to their name. The agency estimates as many as 58,000 of those people have voted "in one or more Texas elections."

The Secretary of State's office notes that, while it can't enforce election law, it has shared the list of voters with the Texas attorney general's office and registrars across the state.

In a statement after the announcement, Attorney General Ken Paxton said his office will work with the secretary's office to prosecute cases of voter fraud.

“Every single instance of illegal voting threatens democracy in our state and deprives individual Texans of their voice," Paxton said. "We’re honored to have partnered with the Texas Secretary of State’s office in the past on voter initiatives and we will spare no effort in assisting with these troubling cases."

The secretary's office added that it would continue using DPS data to compile monthly lists going forward. DPS used a combination of first and last names, Social Security numbers, DPS-issued identification numbers and dates of birth to compile the list of voters.

Zenen Perez, a spokesperson for the Texas Civil Rights Project, said the nonprofit has “some big questions” about how the agency got those numbers. He said it's problematic that the Secretary of State's office doesn't divulge its methodology completely and that the numbers are "highly suspect."

Perez said he’s concerned the state is continuing to go after supposed voter fraud, even though there has been little evidence illegal voting is a "rampant" problem here, as Paxton and other state lawmakers have asserted.

Ultimately, Perez said, the decision could disenfranchise some Texas voters.

“We are really concerned that the actions that they are outlining today might result in tens of thousands of eligible voters being removed from the rolls,” he said.

The Secretary of State said it will send out letters to voters suspected of being non-U.S. citizens. If voters wish to contest that designation, they can send either a copy of their birth certificate, their passport or their certificate of naturalization to their county registrar. If they don't contest within 30 days, they will be purged from their registrar's voter rolls.

The League of Women Voters of Texas noted that the Secretary of State said it still needs to cross-check the list against a federal immigration database. League President Grace Chimene applauded the advisory's emphasis on due process before counties start purging voter rolls.

"Mistakes can be made, and citizens deserve the opportunity to correct them," she said in a statement.

Chimene said the report also showed the state needs to "modernize" the voter registration system and called on the Legislature to act.

"There are multiple bills already introduced that can improve [the system's] integrity. Tying use of a continually clean and accurate DPS database of citizens/non-citizens is very doable," she said.

Voters can check their status at the Texas Secretary of State's website.

This post has been updated.

Ashley Lopez contributed to this report.