The Portland Police Department declared a riot Saturday when protesters in the Oregon city broke into a building, set it on fire, and lit dumpster fires, according to Fox News.

“The fire at the Portland Police Association building was put out a short time later, Portland police said on Twitter. The department declared the gathering a riot, and began working to clear the downtown area,” the article stated.

As police dispersed the crowd, they arrested several protesters and scattered others into a nearby neighborhood, the department said in a press release Sunday.

The release continued:

A large number of people regrouped near North Interstate Avenue and North Lombard Street. Portland Police Officers moved the crowd to the south on North Interstate Avenue. As they did, people in the crowd threw rocks, gopher gassers, and launched paint filled balloons at officers. Some officers were injured. By about 11:30 p.m., the crowd was broken into small groups and order was restored.

During this activity in north Portland, another large crowd was downtown near the Justice Center and Federal Courthouse. People tore down fences around Chapman Square Park and Lownsdale Square Park which had been put in place recently when the parks were closed for needed repair.

“People also removed fencing around the Federal Courthouse and used it to barricade doors there. Others moved fencing in front of west and north doors to the Justice Center,” the release stated.

Recently, federal law enforcement officers reportedly began detaining protesters in unmarked police vehicles in an effort to stop the violence.

However, during a Sunday interview on CNN’s State of the Union, Portland Mayor Ted Wheeler (D) called their actions “completely unconstitutional” and claimed their presence was “leading to more violence and more vandalism.”

“And it’s not helping the situation at all. They’re not wanted here. We haven’t asked them here. In fact, we want them to leave,” he continued.

Despite the pushback, President Donald Trump said in a tweet Sunday that the officers were trying to help the city.