Seattle police declare riot after 20-plus officers injured, 'explosive' fires set in Capitol Hill

Police declared a riot Saturday afternoon after another day of peaceful protest was hijacked by looters who injured 21 police officers, lit "explosive" fires and caused widespread damage in the city's Capitol Hill neighborhood. 

Hundreds of people gathered about 2 p.m. Saturday for a peaceful march in solidarity with protesters in Portland who are facing arrest by federal agents. By 4 p.m., crowds had broken away from the peaceful protest, setting fires to five construction trailers at the Juvenile Detention Center and attacking camera crews. 

One officer was hospitalized with a knee injury caused by an explosive. A Harborview Medical Center spokesperson said the officer is in satisfactory condition as of Saturday evening. SPD said as of 10 p.m., 21 officers were injured by bricks, rocks, mortars and other explosives.

At least 45 people were arrested for assault on officers, obstruction and failure to disperse.

Police reported multiple explosions in the area and numerous fires, including one inside the East Precinct, where rioters breached a security fence to vandalize the building. Police are investigating "explosive damage" to the walls of the East Precinct and more explosives being thrown at police.

A Starbucks on 12th was destroyed. Countless storefronts were tagged with profane graffiti. 

RELATED: Seattle leaders worried federal presence will inflame tensions this weekend

It's the third day this week rioters have targeted businesses and government buildings and the second time this week that officers have been hurt. On Sunday, 12 SPD officers were injured and one was sent to the hospital with a neck burn after being hit with fireworks. 

Police are able to use pepper spray and blast balls to disperse the crowds after a federal judge intervened Friday night and blocked a Seattle City Council ordinance banning police from using crowd-control measures. 

The King County Sheriff's Office has been called in to assist SPD. 

Federal agents were deployed to Seattle Thursday evening to protect federal buildings, against the wishes of local and state leaders who say their presence will only exacerbate an already tense situation. It's unclear if the federal agents' roles have changed since the riot was declared.