WASHINGTON — The Justice Department is threatening legal action against California unless state and local officials review a list of potential noncitizen individuals on their voter rolls.

Acting Deputy Attorney General R. Trent McCotter on Tuesday sent letters to California Secretary of State Shirley Weber and Los Angeles County Registrar-Recorder Dean Logan with a list of names of possible noncitizens identified by the federal government. The letters demand they review the list by noon on Thursday.

“Allowing noncitizens to vote cancels citizen votes,” McCotter wrote in the letters, which was obtained by NBC News.

McCotter wrote that the DOJ provided a password-protected thumb drive with a list of individuals the federal government “believes are likely noncitizens who were sent a vote-by-mail ballot” for the 2026 election. He asked that county election officials “segregate — not cancel — those individuals’ vote-by-mail ballots” until their citizenship status was determined.

“This should not be controversial, as the criminal statute is clear: only American citizens may vote in federal elections,” a Justice Department spokesperson said in a statement. “It is a federal crime for noncitizens to vote in U.S. elections, and the DOJ is asking California to ensure that is not occurring.”

Reuters first reported on the letters.

Justin Levitt, an NBC News contributor who was a Justice Department official during the Obama administration, said the federal government has no authority supporting its demands.

“They can send the letter,” he said. “California doesn’t have to do anything about it.”

Federal law prohibits systemic list maintenance within 90 days of a federal election. At this point, less than three weeks out from Election Day, the only changes to the voter rolls can come from individualized information, like notification from the Social Security Administration that someone has died.

A DOJ spokesperson said the department is asking California to sequester ballots, not change their voter list.

In a statement Wednesday, Logan said his office had not accessed the thumb drive the DOJ provided “because doing so would conflict with established data privacy and information security protocols.” He added, “We do not consider the device a secure medium.”

“Maintaining accurate voter registration records is a fundamental responsibility of our office,” Logan said in the statement. “Federal and state laws are clear on how voter eligibility is established — and any action to remove a voter from eligibility must be based on verifiable information, not assertions of unconfirmed data matching.”

Weber said in a statement Wednesday that the DOJ did not provide a list of purported noncitizens to her office and that the administration lacked the legal authority for its request.

“The USDOJ’s relentless efforts to unlawfully gain access to states’ protected voter data and purge voter rolls serve only to cause chaos and fuel public distrust in our elections,” Weber said in the statement. “California has robust state law requirements that only U.S. citizens can register to vote and that any non-eligible registrants are removed from the State’s voter rolls. My office and California election officials remain committed — as always — to ensuring a fair and smooth 2026 General Election.”

All registered voters in California receive mail-in ballots, which started going out on Oct. 5.

The legal threats came amid a broader campaign by the Trump administration to zero in on what voting experts say is a relatively rare phenomenon of voting by noncitizen individuals. Trump has long made unfounded claims that voting is marred by widespread fraud.

Election officials in several states — including Georgia, Connecticut, Nevada and Washington state — say they have received federal subpoenas in recent months for election records.

Some officials said they fear these actions were designed to set up possible legal challenges after the midterm elections.

“What we have seen is some groundwork laid out for postelection challenges,” said Stuart Holmes, the director of elections in Washington state. “Whether that’s the seizure of voting equipment, ballots themselves, tabulation equipment ... we’re preparing for any and all eventualities in that case.”

Nevada Secretary of State Cisco Aguilar, a Democrat, said officials in his state are also preparing for potential challenges to this November’s results. He added that he viewed the administration’s moves as “an effort to dissuade people from participating in the elections.”

“You have a president who’s trying to choose the voter base rather than the voters choosing the elected, and that’s not how our democracy works,” he said in an interview. “It’s the people control our elections, and when you try to take that control out, you do it through intimidation, you do it through threats, and you do it by trying to dissuade people from participating.”

Levitt agreed with the election officials’ conclusions.

“Are they laying the groundwork to say that voting was fraudulent? Of course they are, 100% they are,” he said, referring to the Trump administration. “Is the boy who cried wolf going to cry wolf? Yes, that’s what the boy who cried wolf does.”

Since Trump took office, his administration has brought over 100 cases involving allegations of voting by noncitizens. More than 154 million people voted in the 2024 election, according to the U.S. Census Bureau.

During the second Trump administration, the DOJ has sought voter registration data from every state in the country. It has filed lawsuits against 30 states and Washington, D.C., for refusing.