Protesters piled up road signs and plastic barriers and lit a blaze in the middle of H Street, shortly before the start of the 11 p.m. curfew imposed by Washington, D.C. Mayor Muriel Bowser.
Some of the demonstrators pulled an American flag from a nearby building and threw it into the flames, The Associated Press reported.
The basement of The Parish House in historic St. John’s Episcopal Church, near Lafayette Park, was in flames, according to live footage from Fox News.
Another blaze was consuming a public cinder block building with bathrooms and a maintenance office at the edge of the park.
Police formed a line to push back the crowd of more than 1,000 people, firing tear gas and stun grenades, and largely clearing the park, which is across the street from the White House.
A senior official told Fox News that at least 50 U.S. Secret Service members had been injured by Sunday night.
Earlier in the day, hundreds of people had converged on the White House and marched along the National Mall, chanting “Black Lives Matter,” “I can’t breathe” and “No justice, no peace.”
The Executive Mansion was unusually quiet for a Sunday as staffers were encouraged to stay away because of the ongoing demonstrations, according to NBC 4 Washington.
During the second night of protests on Saturday, 17 people were arrested and 11 D.C. cops were injured.
Several famed monuments were defaced, including the Lincoln Memorial, the World War II Memorial and the statue of General Casimir Pulaski, according to the National Mall National Park Service.
Bowser ordered the curfew for city residents on Sunday, and it will be in effect until Monday at 6 a.m. She also activated the D.C. National Guard to support local cops.
With Post wires