Police in Portland used tear gas early Monday to scatter demonstrators who marched on a precinct station in another night of violence - hurling rocks, bottles, commercial-grade fireworks at officers and setting fires in the streets.

The protests have gripped Oregon's largest city for months since the police killing of George Floyd in Minneapolis and demonstrators in Portland Sunday night who marched to the precinct from a park chanted the name Jacob Blake.

Wisconsin Gov. Tony Evers identified him as the man who appeared to be Black who had been shot in the back by a police officer in Kenosha on Sunday.

Some of the Portland protesters in a group of about 200 lit a dumpster on fire and used it as a shield as they approached the police precinct station, police said in a statement. They threw things at officers, hitting some who were posted on the precinct station's roof, and lit one of the building's awnings on fire, the statement said.

Some protesters were arrested but the statement did not say how many. One officer suffered a wrist injury when he was hit with piece of ceramic, the statement said.

The violence that started Sunday night and lasted into the predawn hours of Monday came a day after protesters targeted another law enforcement building in Portalnd.

The protesters apparently had plans Saturday night to march from a park to the building, news outlets reported. But a standoff between marchers and officers took place on a bridge along the way _ and the demonstrators retreated.

Protesters appear to have returned to the park and then took cars to the building. Officers were then hit with rocks, bottles and other objects, police said.

That unrest followed rival protests Saturday afternoon in downtown Portland.

Federal authorities forced demonstrators away from a plaza near a federal building as dueling demonstrations by right-wing and left-wing protesters turned violent.