Department of Homeland Security officers form a line Saturday at Terry Shrunk Plaza as far-right demonstrators with the stated goal of "Saying No to Marxism," clash with counter-protesters in Portland, Oregon. Credit: Brooke Herbert / The Oregonian via AP

PORTLAND, Oregon — A police precinct was set on fire during a protest in Portland, Oregon, prompting authorities to declare a riot and deploy tear gas to disperse the demonstrators.

The fire burned an awning at the north precinct late Sunday, news outlets reported. Police ordered demonstrators to clear the area, saying that rocks and glass bottles had been thrown at officers, as well as lasers pointed their direction. An unlawful assembly had been declared before the gathering was deemed a riot.

The tear gas was deployed after the fire had been set, according to news outlets. Protesters had marched to the precinct from a park, chanting several things including “Jacob Blake,” who Wisconsin Gov. Tony Evers identified as the man shot by a police officer in Kenosha on Sunday. Authorities in Wisconsin had not confirmed the person’s name.

Violent demonstrations have gripped Portland for months, following the police killing of George Floyd in Minneapolis police custody.

Early Sunday police forced protesters away from a law enforcement building, as efforts to stop the demonstrators from gathering at the building seemingly fell apart.

The protesters apparently had plans Saturday night to march from a park to the Penumbra Kelly public safety building, news outlets reported. But a standoff between marchers and officers took place on a bridge along the way — and the demonstrators retreated.

Protesters appear to have returned to the park, and then taken cars to the building. Police initially declared an unlawful assembly, saying items had been thrown at officers, green lasers had been pointed at officers and a support airplane and paintball guns had been fired.

The gathering was later declared a riot. Officers had been hit with rocks, bottles and other objects, police said. Numerous officers reported seeing people with some type of “press” identification throwing rocks at them, authorities said.

The unrest followed rival protests Saturday afternoon. Federal authorities forced demonstrators away from a plaza near a federal building as dueling demonstrations by right-wing and left-wing protesters turned violent.