Texas Attorney General Ken Paxton on Wednesday issued cease and desist letters to three Texas school districts he says are conducting "unlawful electioneering," adding one more chapter to an ongoing fight over how involved public education organizations can get in this year’s primary and general elections.

Paxton, a Republican, warned the Brazosport, Holliday and Lewisville districts that they are violating state law by using taxpayer money to distribute messages advocating for specific candidates and policies to their staffs.

“These school districts must understand that they are responsible, as all state agencies are, for refraining from spending public funds on advocating for or opposing political candidates,” Paxton said in a statement Wednesday. “The electioneering of these school districts is unacceptable and a poor example of the civic responsibility, integrity, and honesty that Texas educators should model for our students.”

Paxton’s letters emphasize that while school districts may promote civic engagement and register students to vote, they are not permitted to “use state or local funds or other resources to electioneer for or against any candidate, measure or political party.”

Paxton specifically called out school officials for using public accounts and school dollars to express opinions on particular candidates. Many of the school districts' social media accounts have tweeted or retweeted stances on public education issues in the upcoming elections.

Some of the posts Paxton identified advocate for particular candidates or policies, while others more generally encourage voting in support of public education.

Brazosport Superintendent Danny Massey, for example, has tweeted in support of Scott Milder, a Republican candidate for lieutenant governor. That tweet was retweeted by the Brazoswood High School Twitter account, according to Paxton's letter.

Paxton called out Lewisville ISD for a tweet from the district's account which read, "We are asking for support from our state Legislature. We're not getting it. It's time for change."

In a statement, Lewisville ISD officials said the district "respectfully disagrees" with the attorney general on this matter, adding that the tweet was taken down a day after it was posted.

"We dispute any characterization of the district’s get out the vote campaign as anything other than an effort to engage the LISD staff and community in their constitutional right to vote and advocate for themselves," the district said in a statement. "The district will reiterate again with staff that they alone can make the decision to support a candidate and measure, and the district does not wish to impose the beliefs of its Board or Superintendent."

Superintendents in the other two districts did not immediately return requests for comment Wednesday.

Tensions have been simmering between public education advocates and certain conservatives for months, in part over a “culture of voting” resolution championed by a civic engagement group. That resolution, some conservatives have alleged, amounts to illegal electioneering by government entities. Education advocates counter that they are merely gearing up to vote en masse after 2017’s regular and special session of the Texas Legislature failed to resolve several key public education issues – and they insist that they have not run afoul of the law.

That dispute reached the attorney general’s office in December, when state Sen. Paul Bettencourt, R-Houston, asked Paxton to weigh in on one of the resolution’s measures. That provision asks school districts to consider using school vehicles to bus students and teachers to the polls if district policy allows. Paxton ruled last month that school districts cannot provide transportation to polling places unless the trips serve an “educational purpose.”

The fight for the lieutenant governor’s office looms large in the ongoing dispute. Milder, a public education advocate, is challenging conservative favorite Lt. Gov. Dan Patrick in this year’s Republican primary. A conservative group has sent open records requests to several school districts requesting information about Milder, citing complaints from teachers that Milder’s campaign newsletter was disseminated to school personnel.