Two women were seriously injured after a car hit a small group of protesters on a closed highway in Seattle, authorities say.
The car “went through the lock and hit several pedestrians,” said a tweet from the Washington State Patrol.
One of the women is reported to have fatal injuries and a suspect has been arrested.
There have been riots in Seattle since African-American George Floyd died in police custody in Minneapolis in May.
Protests have spread across the United States under the Black Lives Matter movement.
The vehicle incident occurred in the early hours of Saturday in a section south of Interstate 5 that had been closed prior to a women’s march.
Part of the protest was broadcast live on social media under the title “Black Femme March takes I-5”.
The images posted on Twitter showed a white car speeding down the road, before swerving to avoid two stationary vehicles positioned as an obstacle on the road and then hitting the two people.
The Associated Press quoted Washington State Patrol Captain Ron Mead as saying that a 24-year-old Seattle woman had been seriously injured and a 32-year-old Bellingham woman was seriously injured.
He said the driver was a 27-year-old Seattle man and it was not known if it was a targeted attack.
The injured protesters were taken to Harborview Medical Center, the Seattle Fire Department said.