Portland Police Association vandalized
© Twitter / @45thabsurdist
A mob broke into the office of the Portland police union and set a small fire to the building amid growing hostility between demonstrators and law enforcement in the city. The blaze was later put out as officers cleared the area.

A group of demonstrators targeted the Portland Police Association office on Saturday night, barricading a nearby street and lighting dumpsters on fire.

Several videos of the incident show protesters outside the breached door of the building.

Other footage shows the office's interior glowing orange from the blaze inside.

In a Twitter update, the Portland Police Bureau said that officers had extinguished the blaze and "restored order to the neighborhood." Law enforcement declared the anarchic situation a riot and used tear gas to disperse the crowd that had gathered around the building.

Elsewhere in the city, protesters dismantled fences and barriers used to protect Portland's federal courthouse. The building has become the main flashpoint between law enforcement and demonstrators.

Federal agents charged with guarding the site have come under scrutiny, after being accused of seizing and detaining protesters without probable cause.

Meanwhile, Oregon's attorney general has sued the Department of Homeland Security and other agencies in order to end the alleged practice, while Portland's mayor has banned federal police from sharing headquarters with city police.