At least two people were arrested during the unrest, one for property damage and another for assault, according to the Seattle Police Department. Police later announced a man had been arrested "for investigation of burglary and for the property damage" after a glass storefront was damaged at a Starbucks in the city.
Seattle police tweeted photos of the damage and said multiple sites were vandalized, including what appeared to be an Amazon Go store. Multiple windows were also shattered at the William Kenzo Nakamura Courthouse, police said.
The protests started around 4:30 p.m. local time, with a handful of people gathering at a park before they started marching through the streets of downtown Seattle.
The group had initially been carrying a sign that read "Abolish ICE," [U.S. Immigration and Customs Enforcement] while another banner suggested they were protesting Biden and law enforcement, according to reports.
Some of the protesters threw objects to block motorists and target those who weren't taking part in the demonstration, according to Seattle's KOMO-TV.
The station reported that several vehicles were damaged before authorities issued an order for the group to disperse. At one point, the protesters lit an American flag on fire in the middle of an intersection, which was "quickly put out," according to Seattle's KING-TV.
A crowd of up to 150 people gathered at Revolution Hall around 2 p.m. and marched to the headquarters of the Democratic Party of Oregon, Portland police Sgt. Kevin Allen said.
The so-called J20 protest in Portland was a demonstration against Biden and law enforcement. Some in the group smashed windows, vandalized a building with graffiti, and forced officers to retreat.
Fox News' Louis Casiano contributed to this report.