Seventeen were arrested for hurling objects at police in a Wednesday evening May Day protest in Seattle that turned violent.
Police said in CNN that crowds began to throw rocks, bottles, fireworks, pipes and even a skateboard at police, leaving eight officers injured. Most of their injuries were minor; one, however, was hit hard in the knee with a 4-inch rock.
Meanwhile, a woman driving by the scene was injured when a protester threw a glass bottle at her windshield, CNN reported.
Police ultimately fired off flash-bang grenades to calm the chaos, CNN said.
The 17 who were arrested were charged with destruction of property and with assault, CNN reported.