Members of one activist group, Baltimore Bloc, had announced Tuesday on Twitter that the city planned to take down the statues on Wednesday evening. Instead, at least one of their members watched happily as a statue of Lee and Jackson was hoisted off its pedestal, posting a video on Twitter and writing, “Move Lee, get out the way, get out the way Jackson, get out the way.”

The city had been studying what to do with its Confederate monuments since 2015, when a mass shooting by a white supremacist at a historic black church in Charleston, S.C., led to a renewed debate across the South about removing Confederate monuments and battle flags from public spaces.

Ms. Pugh said she had been working on the removal of the statues since June, when she met with Mayor Mitch Landrieu of New Orleans to discuss his city’s removal of its own Confederate monuments. By last week, she said she had reached out to contractors to solicit assessments on the feasibility of removing each of the statues in short order, and sped up her efforts after watching the violence in Charlottesville on Saturday.

Ms. Pugh said she did not anticipate a legal challenge but that the city would fight any suit.

“I don’t think it would matter, because I think having consulted with my legal team I acted in the best interest of my city,” she said,

The mayor said she did not know where the statues were moved or where they will end up. She suggested plaques be installed that describe “what was there and why it was removed.”

Maryland never seceded from the Union in the Civil War, but there was popular support for the Confederacy in Baltimore and southern Maryland, where Confederate soldiers are buried. The monuments, here in a majority-black city, are considered widely offensive because of their ties to slavery and the Confederacy.