Officers found a crowbar, hammers, bear spray and firearms after they corralled a group of about 100 protesters, Portland police said Saturday.

In a news release, the police bureau said officers surrounded the protesters about 15 minutes after the march began Friday night in the city’s Pearl District at 9 p.m. because some began smashing windows.

The department said it warned the crowd that failure to comply with lawful orders could result in arrest and exposure to tear gas, and it invited news reporters, legal observers and anyone with medical conditions to leave the enclosed area.

Those who left were identified and photographed as part of an investigation, police said. Others locked arms and refused; officers escorted them away and arrested them, including a suspect in the earlier window vandalism, officers said.

Some of the protesters also confronted the police, throwing rocks and full cans of beer, the department said. Officers used pepper spray.

Among the items left behind by the protesters were crowbar, hammers, bear spray, knives and what the department described as a “slugging weapon with rocks.”

Thirteen people are facing charges from the protest, including disorderly conduct, resisting arrest and interfering with police.

One, identified as Katrina Walker, 26, of Portland, was cited for unlawful possession of a firearm; another, Tara Walker, 34, was booked for unlawful possession of a firearm and possession of a loaded firearm in a public place, among other charges. It was not immediately known if they were related or if they had attorneys who might speak on their behalf.

On Saturday, three civil rights groups called for U.S. Attorney General Merrick Garland to investigate the Portland Police Bureau in light of Friday’s arrests.

In a statement, the Oregon Justice Resource Center, the Council on American-Islamic Relations of Oregon and the American Civil Liberties Union of Oregon said: “Under the authority of Mayor and Police Commissioner Ted Wheeler and Police Chief Chuck Lovell, what PPB did last night — kettling — is an aggressive and indiscriminate police tactic of surrounding and boxing in a group of people and blocking off all exit points.

“Both the Oregon Justice Resource Center and ACLU of Oregon are currently representing clients in federal lawsuits against PPB’s use of the kettling tactic against anti-Trump protesters in 2017. In neither case has the court approved of or found constitutional this abusive tactic.”

Portland has been the site of frequent protests, many involving violent clashes between officers and demonstrators, ever since the police killing of George Floyd in Minneapolis in May. Over the summer, there were demonstrations for more than 100 straight days.

Mayor Ted Wheeler has decried what he described as a segment of violent agitators who detract from the message of police accountability and should be subject to more severe punishment.

(AP)