PORTLAND, Ore. (NewsNation) — Fires set outside a law enforcement building that’s a frequent site for protests in Portland, Oregon, prompted police to declare a riot early Saturday and detain several demonstrators.

Witnesses also said a car drove near the demonstration at the Portland Police Association building and fired several gunshots into the air. Video posted online showed shell casings in the street. No injuries were reported.

Officers had extinguished the fire at the police building and appeared to detain several protesters. It was unclear how many were arrested.

The commotion followed a sit-in in the lobby of the Portland mayor’s condo building Friday night. Protesters have issued demands, including police budget reductions and Mayor Ted Wheeler’s resignation, the Oregonian/OregonLive reported.

A crowd of about 150 had gathered outside the building. At least three people locked themselves inside the complex in the hopes of expressing their demands, NewsNation affiliate KOIN reported.

Portland has been gripped by nightly protests for three months since the police killing of George Floyd in Minneapolis. The demonstrations, often violent, usually target police buildings and federal buildings. Some protesters have called for reductions in police budgets while the city’s mayor and some in the Black community have decried the violence, saying it’s counterproductive.

Protesters also took to the streets Friday in solidarity with Jacob Blake, a Black man who was shot seven times by police in Kenosha, Wisconsin, nearly one week ago. Blake is still recovering from his injuries.

“Rest in peace, rest in power to everyone who was executed due to injustice,” said rapper Swiggle Mandela, who created a song played regularly at protests called “Dear Portland Police.” “No matter where you come from, no matter how you identify with yourself, no matter what color your skin is, we’re all one family.”

Some demonstrators said Kenosha serves as a reminder of the dangers protesters face after two men were fatally shot during a night of unrest following the police shooting. Kyle Rittenhouse, 17, of Antioch, Illinois, faces charges of intentional homicide, reckless homicide, attempted intentional homicide and reckless endangerment in the shooting.

“There’s huge concerns here that things are going to escalate again in a way that’s absolutely terrifying,” said Marie Tyvoll, a medic tent organizer who helps distribute supplies to protesters.

“Some people are so hateful it’s like their heritage, like it’s something that it’s hard for them to escape, so you just never know who’s going to do what,” Swiggle Mandela added.

On Friday, Portland Mayor Ted Wheeler sent an open letter to President Donald Trump, declining his offers to send federal enforcement to help the city manage the protests.

In early July, Trump sent more federal agents to the city to protect the federal courthouse, but local officials said their presence made things worse. The federal agents later pulled back.

Meanwhile, 74 people are now facing federal charges related to protests that have rocked Portland for three months since George Floyd was killed, the local U.S. attorney announced Thursday.

The misdemeanor and felony charges include assaults on federal officers, arson and damaging federal property.

The Associated Press and NewsNation affiliate KOIN contributed to this report.