Several cars in the area of 12th and K streets had their windows blown out by protesters around 4:30 p.m. A limo along the road was then set on fire, sending black smoke billowing into the sky.
By 4:45 p.m., firefighters had contained the blaze.
Dozens of police officers wearing riot gear were seen walking toward the scene.
D.C. Interim Police Chief Peter Newsham noted that there are several protests happening around the city that are peaceful.
Police have arrested more than 100 protesters.