PORTLAND, Ore. (KOIN) — Portland police declared a riot late Thursday after people broke windows of downtown buildings, shot off fireworks at the federal courthouse and set fires.

Police declared the riot in Portland at around 10:50 p.m. PST, warning that those in the area could be subject to “riot control agents” if they don’t leave.

Roughly 20 minutes later, police advanced on the protesters, who responded by shooting fireworks at them.

NewsNation affiliate KOIN reported that pepper spray or mace was used, and the sound of pepper balls, rubber bullets or some type of less lethal munition was heard.

The unrest began around 9 p.m. when a group of protesters gathered downtown near police headquarters before marching through the streets. A window of a Starbucks was broken, and some in the group began shooting off fireworks.

The police department was vandalized, along with several other buildings, before people began shooting fireworks at the Mark O. Hatfield Federal Courthouse building. A crosswalk sign appeared to be one of several fires spotted around 10:40 p.m. as people banged on the Justice Center.

The reason for the gathering remains unclear at this time.

The unrest comes one day after nearly a dozen businesses were vandalized downtown, including City Hall, the Portland Police Bureau and the Oregon Historical Society, according to police.

Around 7 p.m., a group of approximately 40 people marched out of Director Park and through various streets, causing damage along the way, police said. That included breaking windows, spray painting buildings and the firing of paintballs. A police officer tried to contact one of the people, but their police vehicle was then spray painted, police said.

No arrests have been made and the investigation is still ongoing.