The statues were taken down by order of Mayor Catherine Pugh, after the City Council voted on Monday for their removal. The city had been studying the issue since 2015, when a mass shooting by a white supremacist at a historic black church in Charleston, S.C., prompted a renewed debate across the South over removing Confederate monuments and battle flags from public spaces.
The police confirmed the removal.
By 3:30 a.m., three of the city's four monuments had been removed. They included the Robert E. Lee and Thomas J. "Stonewall" Jackson Monument, a double equestrian statue of the Confederate generals erected in 1948; the Confederate Soldiers and Sailors Monument, erected in 1903; and the Roger B. Taney Monument, erected in 1887.
Taney was a Supreme Court chief justice and Maryland native who wrote the landmark 1857 decision in the Dred Scott case, ruling that even free blacks had no claim to citizenship in the United States. Although Taney was never part of the Confederacy, the court's decision was celebrated by supporters of slavery.
The fourth statue, the Confederate Women's Monument, was dedicated in 1917. Pictures showed that it too had been taken down early on Wednesday.
One Twitter user, James MacArthur, live-streamed the removal of the Lee and Jackson monument as it was unceremoniously torn from its pedestal and strapped to a flatbed truck. At street level, lit by the harsh glare of police klieg lights, the two generals appeared small.
Residents were seen celebrating on the pedestal, on which someone had spray-painted "Black Lives Matter."
A team of police cars escorted the statues out of town. Ms. Pugh suggested on Monday that the statues might be relocated to Confederate cemeteries elsewhere in the state. (Although Maryland never seceded from the Union during the Civil War, there was popular support for the Confederacy in Baltimore and Southern Maryland, where Confederate soldiers are buried.)
One city councilman said the statues should be destroyed, not just moved.
"These people were terrorists. They were traitors. Why are we honoring them?" Councilman Brandon M. Scott said at a meeting on Monday.
A group of protesters made up of so-called alt-right activists and white supremacists demonstrated against the removal of a Lee statue in Charlottesville, Va., on Saturday, clashing with counter-protesters. One woman was killed when a driver rammed a car into a crowd of counter-protesters; the police have charged an Ohio man who has expressed far-right views. Two state troopers monitoring the event were also killed in a helicopter accident.
Tensions were further inflamed on Saturday when President Trump refused to clearly denounce the protesters, some of whom carried Nazi banners and Confederate battle flags. Although he condemned the Ku Klux Klan, "neo-Nazis, white supremacists and other hate groups" in a statement on Monday, Mr. Trump said Tuesday that parties on "both sides" of the debate were to blame for the deadly violence.