At least 25 people were arrested Monday when a May Day rally in Portland, Oregon, turned violent. The event, originally a march for labor rights, grew chaotic after police and self-proclaimed anarchists came into conflict, with the anarchists throwing smoke bombs, Pepsi cans, and other objects at police, and officers firing non-lethal projectiles in return. The face-off escalated with businesses’ windows shattered, bonfires set in the streets, and at least one police vehicle attacked. Police eventually declared the march a riot and canceled its permit at 4:30 p.m., ordering attendees to disperse. Police threatened to arrest anyone in the streets after the permit was canceled early in the evening.