Two women have now been seriously hurt after a car careered in to a small number of protesters on a closed highway in Seattle, officials say.
The car “drove through the closure and struck multiple pedestrians”, a Washington State Patrol tweet said.
One of the women reportedly has life-threatening injuries and a suspect has been arrested.
There has been unrest in Seattle since African American George Floyd died in police custody in Minneapolis in May.
Protests have been widespread across the US under the Black Lives Matter movement.
The incident with the automobile occurred in the early hours of Saturday at a southbound area of Interstate-5 that were shut before a women’s march.
Part of the protest had been live-streamed on social media marketing under the headline “Black Femme March takes I-5”.
Footage posted on Twitter showed a white car speeding across the highway, before swerving in order to avoid two stationary vehicles positioned as a roadblock, then hitting the 2 people.
Associated Press quoted Washington State Patrol Captain Ron Mead as saying a 24-year-old woman from Seattle had suffered life-threatening injuries and a 32-year-old woman from Bellingham had serious injuries.
He said the driver was a 27-year-old man from Seattle and it was unknown if it was a targeted attack.
The injured protesters were taken fully to Harborview Medical Center, the Seattle Fire Department said.