A grand jury in New Orleans indicted Louisiana’s Republican attorney general on Thursday over letters she had sent city officials threatening that they could be removed from office. The development came after months of tension between New Orleans and state officials who have exerted their power over the city.

The 16-count indictment charged Attorney General Liz Murrill with malfeasance in office and intimidation and retaliation against a public official, a special prosecutor told reporters outside the county courthouse.

Gov. Jeff Landry condemned the charges, calling the city’s criminal justice system “a circus at its finest,” and said he would pardon Ms. Murrill “as fast as the law allows.”

The tensions — the latest front in a long-running conflict between the left-leaning city and Louisiana’s conservative state government — were the result of a push by state lawmakers to reconfigure the New Orleans judicial system. It included merging the separate elected offices of the criminal and civil court clerks into a single role.

State lawmakers said the merger eliminated the criminal clerk’s office, shifting its responsibilities and funding to the civil court clerk. But New Orleans officials argued that the state had, in fact, created an entirely new office: the clerk of courts. In May, the City Council appointed a retired judge to the post and called a special election, all while the sitting civil court clerk continued to serve.

Ms. Murrill, a Republican, sent warning letters on May 13 to eight elected officials, including Mayor Helena Moreno; Jason Williams, the district attorney for New Orleans; Judge Calvin Johnson, the interim clerk appointed by the city; and five City Council members who had voted in favor of appointing Judge Johnson.

In the letters, Ms. Murrill asserted that the city’s actions “trigger serious consequences under Louisiana’s usurper statutes, including the possible forfeiture of your own office.” She said the officials had “put your own offices in jeopardy” and that Governor Landry, a Republican, had the power to appoint replacements.

She also warned the city officials to “take no further action supporting or recognizing the fictional new office.”

Ms. Moreno, who is in her first year as mayor, argued that it was Ms. Murrill who was violating the law by threatening elected officials for not bowing to the will of state.

“I’m not going to be threatened,” Ms. Moreno said in a video posted to social media. “I’m not going to be intimidated. And I won’t back down.”

The grand jury began investigating the attorney general’s letters on its own volition, which it had the authority to do, prosecutors said. Once the jury took up the matter, Mr. Williams, the city’s chief prosecutor, recused himself, because he had received one of the letters.

A judge appointed Laurie A. White, a retired elected criminal court judge, as a special prosecutor to handle the case. (Ms. White, who served from 2007 to 2023, ran as a Democrat.)

Representatives for Ms. Murrill did not immediately respond to a message seeking comment on Thursday.

In the news conference outside the city’s criminal courthouse, Ms. White said she was simply following the determination of the grand jury. But she acknowledged that the mounting state-city tensions could have been a factor in the panel’s decision to investigate Ms. Murrill.

“Aren’t we a little tired as New Orleanians,” she said, “also having everyone in the state kicking New Orleans?”

Asked about the governor’s statement, Ms. White responded, “Well good, let’s get her convicted and then he can pardon her.”