Authorities declared a riot early Sunday in Portland after rioters breached a portion of fencing erected around a federal courthouse.
The Portland Police Bureau said around 1:20 a.m. that "the violent conduct of people downtown" was "creating grave risk of public alarm," prompting the riot declaration.
Video footage showed federal officers responding forcefully after the barrier was taken down with a chain, firing tear gas and making arrests.
Portland police officers were also helping respond, a change from the bureau's extreme stand-off posture in recent days.
Some arrests were made, though it wasn't clear how many. As officers moved to disperse the rioters, some hurled projectiles like bottles and paint balloons at the police while others shot mortar-style fireworks at them.
Peaceful demonstrations have taken place on most days in Oregon's largest city since late May. The protests devolve at night into rioting. Crowds use sophisticated tactics like formations, equipped with shields, lasers, and other tools.
Rioters for the second consecutive night came equipped with electric saws and other items in their ongoing bid to take down the fence, which was placed around the Mark O. Hatfield Courthouse last week to try to de-escalate tensions.
Democratic city and state leaders claim federal forces are escalating the violence but the officers and agents appear to be reacting to criminal actions by the rioters, including damaging federal property and assaulting law enforcement.
"This is just mindless violence and anyone who defends the violence is enabling this to continue," Williams told reporters while standing outside the building.
"These aren't late night demonstrations. This is criminal activity," he added later.
The continued criminal acts came hours after Portland Police Chief Chuck Lovell appealed to members of the public to "stop for violence" and "work for peace."
Police officers "are prepared to respond to locations throughout the city to prevent intentional violence and destruction of property by people using the cover of large crowds, as we have witnessed nearly every night for the past two months," he said in a video message.
Rioters launched fireworks at the courthouse overnight on Friday and tried to take down the fencing. Federal officers launched tear gas and other crowd control munitions to disperse the crowd, and made multiple arrests.
“To be clear, criminals assaulted FEDERAL officers on FEDERAL property…and the city of Portland did nothing,” he wrote on social media. “It’s time Portland join other responsible cities around the country to hold criminals accountable and protect federal property and officers.”