SEATTLE » Demonstrators clashed with police in two cities in the Pacific Northwest late Friday, with marchers throwing rocks and chairs at officers as the evening gatherings spiraled into mayhem.

Earlier demonstrations in Seattle and Portland, Oregon, to decry racism and income inequality were largely peaceful, but protesters who gathered later in the day confronted police, who attempted to keep them from damaging property and disrupting traffic.

In Seattle, police said black-clad marchers threw wrenches, sticks and rocks at officers in the city’s Capitol Hill neighborhood Friday evening, injuring three officers. Police responded with pepper spray and pepper balls and arrested 15 people. Several dozen vehicles were damaged, police said.

"This is no longer demonstration management, this has turned into a riot," said Seattle police Capt. Chris Fowler, who has been in charge of planning police response to May Day activities.

Seattle Mayor Ed Murray said police would work to protect people and property "and will make arrests when necessary."

In Portland, authorities said an unruly crowd hurled projectiles and chairs at officers Friday evening. Police there temporarily closed a major bridge over the Willamette River during the height of the evening commute and pepper-sprayed some demonstrators when a May Day march deviated from its permitted route through downtown.

Police said one officer was assaulted and was taken to a precinct for medical treatment.

A protest that drew more than 1,000 people in Oakland, California, was largely peaceful, though by Friday night a small group of people broke windows, vandalized several businesses, smashed vehicles and set at least one car on fire at several dealerships on the city’s Auto Row. A video posted online shows a protester inside an auto dealership breaking the windows of a car.

There was no immediate word of arrests.

In Austin, Texas, about 200 marchers railing against police brutality closed a downtown bridge with their numbers, but police blocked them from marching onto a freeway.

Marches held in cities from Minneapolis to Denver drew crowds ranging from a few dozens to hundreds of people.

About 1,000 marched in New York at an event that also decried police abuse in the wake of the in-custody death of Freddie Gray in Baltimore.

In Chicago, about 400 people marched, some to protest recent police incidents and some to recognize May Day’s message of workers’ rights.

Richard Malmin, a 73-year-old activist, said he participates every year but this rally was bigger due to the death of Gray, whose spine was severed while in Baltimore police custody last month. On Friday, six police officers were charged in his death.

"This is a turning point, a tremendous turning point that shows finally the country is waking up," Malmin said. "This is a first, really."

While labor unions have long led demonstrations on International Workers’ Day, the May 1 marches got a boost in 2006 when stringent immigration legislation drove hundreds of thousands of demonstrators to rally in the streets. Since then, attendance at the annual rallies has been much smaller.

Some labor and immigrant advocates broadened their message this year to also address police brutality, joining a series of protests underway in several cities over Gray’s death.

In Minneapolis, the group Black Lives Matter encouraged students to leave school on Friday, and some high school students did. They staged a die-in that briefly stopped traffic.

In Los Angeles, a few hundred gathered to encourage the implementation of President Obama’s program to protect millions of immigrants in the country illegally from deportation. They also called for a raise to minimum wage.

Associated Press writers Don Babwin in Chicago, Kristin Bender and Olga Rodriguez in San Francisco, Edwin Tamara in Los Angeles, and Michael Balsamo and Jake Pearson in New York contributed to this report.