(CNN) A divisive statue of Confederate military leader Pierre Gustave Toutant Beauregard won't go down without a legal fight.

Longtime resident Richard Marksbury is suing New Orleans and seeking a temporary restraining order to prevent the city from "touching, removing or doing anything with the Beauregard monument," he told reporters Monday.

Marksbury is a founding member of the Monumental Task Committee -- a group decrying the city's planned removal of Confederate statues.

Those monuments have been the subject of heated protests, which flared up again Sunday.

Protesters demonstrate across the street from the Jefferson Davis monument Sunday.

The city has already removed the first of the four monuments: one commemorating the Battle of Liberty Place . It was erected in 1891 to mark a deadly fight between members of the "Crescent City White League," a group opposed to the city's biracial police force and state militia after the Civil War.

Last month, amid security threats, contractors wearing masks and tactical vests worked in the dark of the night to remove that monument.

Mayor Mitch Landrieu said the city will remove the other three monuments, honoring Beauregard, Robert E. Lee and Jefferson Davis. But the mayor's office said it will not announce when those statues will come down, citing safety concerns.

Why sue?

Marksbury claims the Beauregard monument, which stands at the entrance of City Park, is on private land -- not city land.

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"We now have some documents that I believe will make a difference and show that City Park, as an incorporated association under the lieutenant governor's office, owns the land that the monument is on, and owns the monument," Marksbury said in front of the 15-foot sculpture.

In a letter dated Sunday, Lt. Gov. Billy Nungesser wrote to the president of the New Orleans City Park Improvement Association Board of Commissioners, saying the association owned the statue.

"It has come to my attention that one of the monuments that Mayor Mitch Landrieu is planning to remove is owned by the New Orleans City Park Improvement Association ("CPIA")," the lieutenant governor wrote

Lt. Gov. Billy Nungesser urged the City Park association president to try to prevent the statue's removal.

"I am troubled that the CPIA Board of Commissioners has apparently been aware of this ownership interest for some time now, yet has not exercised its fiduciary duty to protect this valuable state asset."

Nungesser also urged the association to "immediately notify the Mayor in writing of your objection to his removal and seizure of the Beauregard monument." He wrote that the association falls under his purview as commissioner of tourism for the state.

City Park CEO Robert W. Becker issued a statement saying the park has received copies of Marksbury's lawsuit but has not had time to review it.

Landrieu's office has not responded to CNN's request for comment about the lawsuit.

The contentious statue honors a prominent general during the Civil War. Beauregard died in New Orleans in 1893.

In 2015, the words "Black Lives Matter" were spray-painted on both sides of the monument's column, CNN affiliate WDAM-TV reported.

Protests on both sides

Graduate members of Alpha Phi Alpha Fraternity pray near the Jefferson Davis monument last week.

City officials have been trying to move the Confederate monuments since 2015, and pro-statue groups have been protesting ever since.

On Sunday, hundreds of protesters on both sides squared off in New Orleans.

Protesters calling for the removal and the preservation of Confederate-era monuments faced off on Sunday.

Prior to the lawsuit announced Monday, plans to remove the statues appeared to be a legally resolved. In March, a federal judge in Louisiana affirmed the city's right to move the statues.

And the city said it decided to remove the statues afer lengthy public process that determined they "failed to appropriately reflect the values of diversity and inclusion that make New Orleans strong today."

The mayor's office said the city has secured private funding to remove the moments. Landrieu said the statues will go to storage while the city looks for a suitable place to display them, such as a museum.

"We can remember these divisive chapters in our history in a museum or other facility where they can be put in context -- and that's where these statues belong," the mayor said.

In addition to the Beauregard statue, here are are the other monuments the city is planning to remove:

Robert E. Lee statue

The statue of Gen. Robert E. Lee stands in New Orleans' Lee Circle.

The statue honoring Confederate Gen. Robert E. Lee is almost 17 feet tall, stands on a 68-foot pedestal and weighs more than 3 tons. It's located at a roundabout of St. Charles Avenue and Andrew Higgins, not far from the Confederate Memorial Hall Museum.

It was built in 1884 after 14 years of fundraisers and negotiations, the University of New Orleans said.

The group behind its construction was founded about a month after the general's death in 1870 by prominent locals and Civil War veterans.

Last year, the monument was one of several sites vandalized by anti-Trump protesters.

Jefferson Davis statue

Jefferson Davis was president of the Confederate States of America.

The Jefferson Davis monument honors the president of the Confederate States of America, who died in New Orleans in 1889.

The 6-foot-tall bronze statue stands atop a roughly 12-foot tall column, on a street also named after Davis.

In 2004, the words "slave owner" were painted on the base of the monument.