New Orleans was preparing to begin removing the first of four prominent Confederate monuments early on Monday, the latest Southern institution to sever itself from symbols viewed by many as a representation of racism and white supremacy.

Workers arrived to begin removing the first memorial, one that commemorates whites who tried to topple a biracial post-Civil War government in New Orleans, at around 1.25am in an attempt to avoid disruption by supporters who want the monuments to stay, some of whom city officials said have made death threats.

Workers inspecting the statue ahead of its removal could be seen wearing flak jackets and helmets. Police officers watched the area from the top of the car park of a nearby hotel.

Three other statues to Confederate Generals Robert E Lee and PGT Beauregard and Confederate States of America President Jefferson Davis will be removed in later days now that legal challenges have been overcome.

"There's a better way to use the property these monuments are on and a way that better reflects who we are," New Orleans Mayor Mitch Landrieu told the Associated Press on Sunday.

Nationally, the debate over Confederate symbols has become heated since nine parishioners were killed at a black church in South Carolina in June 2015.

South Carolina removed the Confederate flag from its statehouse grounds in the weeks after, and several Southern cities have since considered removing monuments. The University of Mississippi took down its state flag because it includes the Confederate emblem.

New Orleans is a majority African-American city, although the number of black residents has fallen since 2005's Hurricane Katrina drove many people away.

The majority black City Council in 2015 voted 6-1 to approve plans to take the statues down, but legal battles over their fate have prevented the removal until now, said Mr Landrieu, who proposed the monuments' removal and rode to victory twice with overwhelming support from the city's black residents.

People who want the Confederate memorials removed say they are offensive artifacts honouring the region's slave-owning past. But others call the monuments part of the city's history and say they should be protected historic structures.

Robert Bonner, 63, who said he is a Civil War re-enactor, was there to protest over the statue's removal.

"I think it's a terrible thing," he said. "When you start removing the history of the city, you start losing money. You start losing where you came from and where you've been."

Since officials announced the removals, contractors hired by the city have faced death threats and intimidation in the deep South city where passions about the Civil War still run deep.

Mr Landrieu refused to say who the city would be using to remove the statues because of the intimidation attempts. And the removal will begin at night to ensure police can secure the sites to protect workers, and to ease the burden on traffic for people who live and work in the city, the mayor said.

"All of what we will do in the next days will be designed to make sure that we protect everybody, that the workers are safe, the folks around the monuments are safe and that nobody gets hurt," he added.

Mr Landrieu said the memorials do not represent his city as it approaches its 300th anniversary next year. He said the city would remove the monuments, store them and preserve them until an "appropriate" place to display them is determined.

"The monuments are an aberration," he said. "They're actually a denial of our history and they were done in a time when people who still controlled the Confederacy were in charge of this city and it only represents a four-year period in our 1,000-year march to where we are today."

The first memorial to come down will be the Liberty Monument, an 1891 obelisk honouring the Crescent City White League.

Mr Landrieu has called the Liberty Monument "the most offensive of the four" and said it was erected to "revere white supremacy".

"If there was ever a statue that needed to be taken down, it's that one," he said.

The Crescent City White League attempted to overthrow a biracial Reconstruction government in New Orleans after the Civil War. That attempt failed, but white supremacist Democrats later took control of the state.

An inscription added in 1932 said the Yankees withdrew federal troops and "recognised white supremacy in the South" after the group challenged Louisiana's biracial government after the Civil War.

In 1993, these words were covered by a granite slab with a new inscription, saying the obelisk honours "Americans on both sides" who died and that the conflict "should teach us lessons for the future".

The Liberty Monument had been the target of a previous lawsuit after the city removed it from a location on the main thoroughfare of Canal Street during a federally-financed paving project in 1989.

The city did not put the monument back up until it was sued, and moved the monument to an obscure spot on a side street near the entrance to a parking garage.

AP