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PORTLAND, Ore. (AP) — Police in Portland used tear gas early Monday to scatter demonstrators who hurled rocks, bottles and commercial-grade fireworks at officers and set fires in the streets as they marched on a precinct station in another night of violence. Twenty-three people were arrested, police said.

Similar protests have gripped Oregon’s largest city for months after the police killing of George Floyd in Minneapolis.

Demonstrators who marched Sunday night in Portland chanted the name Jacob Blake, a Black man who was shot in the back Sunday by a police officer in Kenosha, Wisconsin.

Some protesters among a group of about 200 people lit a dumpster on fire and used it as a shield as they approached the precinct station, police said.

They threw objects at officers, hitting some positioned on the roof of the station, and lit an awning on fire. One officer suffered a wrist injury after he was hit with a piece of ceramic.

The violence that lasted until early Monday came a day after protesters targeted another law enforcement building in Portland. A standoff between marchers and officers took place on a bridge along the way — and the demonstrators retreated. They apparently returned to a park and took cars to the building, where officers were hit with rocks, bottles and other objects, police said.

On Monday, four people who participated in demonstrations in Portland and say they were tear gassed or hit by impact munitions in July filed a lawsuit against Chad Wolf, acting secretary of the U.S. Department of Homeland Security, and 200 federal law enforcement officers.

Angelica Clark, Ellen Urbani Gass, Nathaniel West and Rowan Maher are named as plaintiffs in the lawsuit, which says the Trump administration unlawfully sent federal agents who used excessive force against peaceful protesters.

The class action lawsuit says tactics used by agents resulted in hundreds of injuries to peaceful protesters.

The Department of Homeland Security did not immediately respond to an email seeking comment.

The FBI said Monday that a threat last week that prompted the closure of a federal courthouse and other federal buildings did not appear to be credible. Among the buildings closed was the Mark O. Hatfield U.S. Courthouse that was a target of protesters who repeatedly clashed in July with federal agents.