RICHMOND — Police used chemicals to disperse protesters Sunday night during another tense stand-off on this city’s historic Monument Avenue, where protesters tried to pull down a statue of Confederate Gen. J.E.B. Stuart using ropes.

Police declared an unlawful assembly about 9:20 p.m., following the attempt to topple the statue, and ordered the large crowd to disperse.

Dozens of city police in riot gear walked shoulder-to-shoulder and forced the protesters to move away from the statue, according to videos posted on social media. State police joined their ranks.

Richmond, the capital of the Confederacy for most of the Civil War, has been the site of nightly protests for much of the last three weeks — part of a national wave of demonstrations calling for racial justice in the wake of the killing of George Floyd in police custody.

The Confederate statues on Monument Avenue have been a focal point for demonstrations, although protesters also have gathered outside police headquarters.

On June 2, Mayor Levar Stoney (D) marched with thousands of angry demonstrators from the state Capitol to the towering statue of Gen. Robert E. Lee after apologizing for officers’ firing chemical gas at peaceful crowds the previous night.

Two days later, Gov. Ralph Northam (D) announced he would remove the Lee statue from state-owned property on the avenue and place it in storage. That plan is being challenged in court.

Last week, Stoney requested and accepted the resignation of Police Chief William Smith, after more tense demonstrations outside police headquarters that involved gas and rubber bullets.

Hours later, protesters toppled the Richmond Howitzers Monument, a Confederate statue near Virginia Commonwealth University’s Monroe Park campus.

Protesters also have taken down statues of Confederate President Jefferson Davis and Christopher Columbus, and covered the bases of all five Confederate statues on Monument Avenue in graffiti. Critics of the demonstrations painted “White Lives Matter” on a statue of African American tennis great Arthus Ashe.

For much of the time, however, the area around the Lee statue has felt more like a street fair than a standoff, especially in daylight, with voter registration, snack tables and people trading slogans and conversation.