NEW ORLEANS — Workers took down a Confederate monument to Gen. P.G.T. Beauregard in New Orleans early Wednesday as onlookers watched from lawn chairs, defiant statue supporters waved Confederate battle flags and opponents celebrated.

It was the third of four such monuments to come down under a plan proposed by Mayor Mitch Landrieu and approved by the City Council more than a year ago. As with two earlier removals, it happened under cover of darkness. Work began soon after sundown and news outlets showed the statue being lifted off its base shortly after 3 a.m.

The statue of Gen. Robert E. Lee will be the last to come down. The city already has removed one of the Confederacy’s only president and a memorial to a white rebellion against a biracial Reconstruction-era government in the city.

“Today we take another step in defining our City not by our past but by our bright future,” Landrieu said in a statement. “While we must honor our history, we will not allow the Confederacy to be put on a pedestal in the heart of New Orleans.”

Landrieu called for removing the monuments in the emotional aftermath of the 2015 massacre of nine black parishioners at a South Carolina church. The killer, Dylann Roof, was an avowed racist who brandished Confederate battle flags in photos, recharging the debate over whether Confederate emblems represent racism or an honorable heritage.

The removal process has been anything but easy.

The City Council voted 6-1 in 2015 to remove the monuments after several contentious public meetings marred by heckling and debate. Contractors in the removal process have been threatened, and the work stalled for months as statue supporters looked in vain to the courts for help.

Those removing the first two memorials generally wore bulletproof vests, helmets and face coverings to shield their identities as the work took place well after midnight to minimize attention.

More recently, lawmakers in the Louisiana House backed a proposal aimed at keeping cities from removing Confederate monuments in a vote Monday that black lawmakers derided as “offensive.”

Workers at the Beauregard removal covered their faces and wore helmets but the atmosphere appeared slightly more low-key. Local media showed a largely peaceful scene of monument supporters waving Confederate battle flags while those supporting removal stood nearby.

Later Wednesday police say they arrested a father and son for allegedly spray-painting the statue’s base with the words “Gen. Beauregard CSA.”

Across a bayou from where the monument stands, some observers sat in lawn chairs, and a brass band celebrating the sculpture’s removal showed up after midnight