Seattle police used pepper spray to disperse black-clad anti-capitalist protesters who, authorities say, threw rocks, flares, bricks and Molotov cocktails at officers during a rowdy May Day gathering.
At least four people were arrested. Authorities said two officers were hurt - one treated at the scene for a head laceration.
Details about the other officer's injury were not immediately available.
The clashes in Seattle followed a peaceful march in the city earlier in the day by advocates for workers and immigrants, just one of several events in cities nationwide yesterday to call for better wages for workers, an end to deportations and support for an Obama administration plan to give work permits to immigrants in the country illegally whose children are American citizens.
Hundreds of May Day marchers chanting slogans and carrying signs "and at least one Donald Trump picture" took to the streets of Los Angeles.
"We want them to hear our voices, to know that we are here and that we want a better life, with jobs," said Norberto Guiterrez, a 46-year-old immigrant from Mexico who joined families, union members and students who marched through downtown.
Demonstrators repeatedly called out Donald Trump for his remarks about immigrants, workers and women. The leading Republican presidential contender has called for a wall on the border with Mexico and chided Democratic hopeful Hillary Clinton for playing the so-called "woman card".
"In addition to fighting for workers' rights, we are fighting for our dignity this time around, our self-respect," said Jorge-Mario Cabrera, a spokesman for the Coalition for Humane Immigrant Rights of Los Angeles.
"We can certainly encourage folks to look at what they're watching, what they're hearing and have them represent themselves and their families whether they can vote or not and say, 'We are not the rapists. We are not the criminals you are talking about. And we are quite good for this country,'" Cabrera said.
Trump says, he is not racist or anti-immigrant; he simply wants the US to stop illegal immigration and control its borders.
Around the world, union members have traditionally marched on May 1 for workers' rights. In the United States, the annual events have become a rallying point for immigrants and their supporters since massive demonstrations in 2006 against a proposed immigration enforcement bill.
In recent years, the marches have waned in size in US cities, but the tradition has continued.
