Later, around 1 a.m. Sunday local time, a large crowd was seen marching near the the Multnomah County Justice Center, the federal courthouse where rioters and protesters frequently gather.
Other videos showed graffiti painted on downtown buildings and showed a fire burning as a crowd gathered.
Journalist Andy Ngo, writing on Twitter, claimed the rioters were burning American flags "while shouting BLM and antifa slogans."
Rioters had been ordered to leave the downtown area ias police moved in against the crowd, OregonLive.com reported.
About 10:30 p.m. local time, police ordered the crowd to stop directing fireworks toward the justice center.