On Monday night, defenders of the statues squared off against a large group of opponents near the Davis statue in the Mid-City area. “Get the hell out of New Orleans,” the multiracial group of opponents sang, to the tune of “The Battle Hymn of the Republic,” using much stronger language, “because you’re not wanted here.”

The police arrested five people on charges of disturbing the peace and other infractions, and city officials have surrounded the statue with barricades and police guards. But the crowds continued to gather, and some defenders of the statues have come heavily armed. A man who referred to himself only as K. K. walked along a median on Tuesday carrying an AK-47, with a Glock handgun on his waist.

Image Frank B. Stewart Jr., a New Orleans native, said removing the statues would be erasing history. Credit... Annie Flanagan for The New York Times

Mr. Landrieu has said the city is sticking to the plan, though it appears that will not be easy. Removing the remaining statues will require the use of a heavy crane, and the mayor told The Times-Picayune that every crane company in the region had received threats.

On Sunday afternoon, anti-statue protesters numbering 500, according to police estimates, took to the streets in a boisterous second line parade through the French Quarter and downtown, ending at Lee Circle, the roundabout where the Lee statue is. There, they faced off against about 150 protesters who had come from all over the country in a show of support for the statue. Some of the counterdemonstators brandished Confederate battle flags. Some exhibited Pepe the Frog insignia and other trappings of the so-called alt-right, a fringe movement that embraces white nationalism. And some wore improvised battle gear, including bike helmets, shin guards and homemade shields.

But the New Orleans Police Department had erected barriers to separate the two groups. Louisiana is an open-carry gun state, but police officials had warned that guns would be banned at Sunday’s protest, citing a city ordinance. One local man had brought large speakers that he used to crank out pop tunes, including Abba’s “Dancing Queen,” a soundtrack that helped transform the proceedings from ominous to farcical.

Beau Tidwell, the communications director for the Police Department, said that three people were arrested Sunday for disturbing the peace over minor scuffles.