"When darkness fell, the counterprotesters triggered more mayhem as they harassed Trump’s advocates, stealing red hats and flags and lighting them on fire."

"Scuffles continued into the night as the provocateurs overturned the tables of vendors who had been selling pro-Trump gear and set off dozens of fireworks, prompting police to pepper-spray them. At 8 p.m., violence broke out five blocks east of the White House between the president’s supporters, who wielded batons, and his black-clad detractors, many of whom had participated in racial justice rallies throughout the summer. As the groups approached the same intersection, they charged each other, brawling for several minutes before police arrived and cleared the area.... [A]lmost none of [Trump's] backers wore masks. Among their ranks were white nationalists, conspiracy theorists and far-right activists carrying signs demanding action that was already being taken: 'Count the legal votes.' Trump had thrilled them when his motorcade appeared on Pennsylvania Avenue shortly after 10 a.m., prompting fans to scramble to the side of Freedom Plaza to catch a glimpse.... 'Trump, pack your [shit]! You’re illegitimate!' [counterprotesters] yelled into their megaphone... A family of four on Capital Bikeshare bikes — the father with an American flag tied around his neck like a cape — were cut off by a line of counterprotesters as they tried to leave a tense scene outside the Supreme Court about 1 p.m. 'Get out of our city!' a young woman in black yelled. 'You lost, losers!' shouted a man. The father and his teenage son began to chant 'U.S.A.!' and raised their fists as police officers surrounded the family and pushed them out of the crowd."

From "After thousands of Trump supporters rally in D.C., violence erupts when night falls" (WaPo).