WASHINGTON - The Trump administration is heightening its conflict with California ahead of next month's midterm election. It warns that local officials who handle and count ballots from suspected noncitizen voters may face criminal investigation and potential prosecution.

The Friday letter from a senior Justice Department official, first obtained by The Associated Press, marks the latest move in an ongoing dispute with heavily Democratic California. It arrives just one day after the Trump administration sued the state to block counting of mail ballots from people the federal government has flagged as likely noncitizens until their immigration status is verified.

The legal consequences for either enabling or overlooking a federal crime are serious. Noncitizen voting in a federal election is a federal crime, and knowingly enabling such conduct is equally unlawful, cautions the letter from Trent McCotter, the acting deputy attorney general at the Justice Department.

It adds: If persons knowingly count ballots cast by individuals identified by federal agencies as noncitizens, they risk becoming aiders and abettors to a federal crime.

The letter is sent to the Los Angeles County Counsel's office and copied to California Secretary of State Shirley Weber and Los Angeles County Registrar Dean Logan, effectively notifying the entire state.

In response to the letter, Logan said his office is focused on running a fair and secure election while noting that Election Day is just 18 days away.

The U.S. Department of Justice has chosen to litigate their unverified assertions of voting eligibility. At this point, it is best for this to be addressed in court, he said.

The other offices and the state attorney general did not immediately respond to requests for comment.

It is unclear how many individuals the Justice Department might seek to investigate and charge, though any federal criminal cases in the Los Angeles area would be handled by the office of Bill Essayli, the region's top federal prosecutor and one of the Justice Department officials who filed the federal complaint Thursday against California.

Trump weighed in late Friday, sharing on Truth Social a link to a news story about the letter and adding: They will all go to jail for a long period of time!!!

Sent less than three weeks before the Nov. 3 election, the letter adds to ongoing tensions over voter rolls between California and the Justice Department and reflects the Trump administration's aggressive pursuit of noncitizen voters. It has made the issue a priority this year, including by demanding detailed voter information including dates of birth, addresses, driver's license numbers and partial Social Security numbers from the states.

The Justice Department has charged about 90 people for various types of election misconduct so far this year, including 50 who are alleged to have voted as noncitizens. There were more than 227 million registered voters in the United States during the 2024 presidential election.

In July, Homeland Security Secretary Markwayne Mullin sent letters to California, Nevada, New Jersey and Pennsylvania, alleging that as many as 250,000 noncitizens were registered in those states. Election officials there were skeptical of the claim, including Weber, the California secretary of state.

That same month, the Republican administration claimed Nevada had 1,500 noncitizen voters on its voter rolls. But after the federal government identified them to the state, the number of actual registered noncitizens turned out to be zero.

That experience is backed up by research and investigations in various states, which make clear that voting by noncitizens is extremely rare.

The Justice Department lawsuit was filed after California officials were given, and did not meet, a 48-hour deadline to review a password-protected thumb drive that contained a list of 20,000 names. The federal government says those are likely noncitizens who were sent ballots to participate in the Nov. 3 election, although the secretary of state said the administration has provided no evidence to support that claim. The state mails ballots to all registered voters.

Rick Hasen, a UCLA law professor, said the letter ups the ante by threatening election officials with potential criminal prosecution.

It is deplorable that rather than work cooperatively and assist states in their election administration responsibilities, the federal government is making escalating threats and unreasonable demands beyond its power in the middle of an ongoing election, he said.

Justin Levitt, a former deputy assistant attorney general who teaches at Loyola Law School in Los Angeles, dismissed the idea that an attempted prosecution of an election official using the letter's rationale would hold up.

Courts have not been buying what DOJ has been selling, and nothing in this letter is calibrated to change course, he said. Fortunately, election officials not just in Los Angeles, but across the country are equipped to stand up to aggressive bullying. And the law is on their side.

Over 23 million people are registered statewide, and a handful of competitive congressional races in other California districts could determine which party controls the U.S. House for the final two years of President Donald Trump's term.

The Trump administration's escalating threats against California come as Democratic lawmakers are urging the Justice Department to honor its longstanding policy of not interfering in U.S. elections.

Earlier Friday, Sens. Alex Padilla, D-Calif., Sheldon Whitehouse, D-R.I., and Dick Durbin, D-Il., wrote to Attorney General Todd Blanche demanding that the Justice Department commit to not seizing ballots or other election materials before the midterm elections are certified.