An anti-capitalist May Day march in Seattle turned violent on Friday when demonstrators threw rocks and wrenches at police, who responded by lobbing "flashbangs" and shooting pepper balls, according to police and media reports.
The Seattle Police Department said on its Twitter account that at least three officers were injured in the scuffle, and at least three people had been arrested.
Footage uploaded on Twitter on Friday evening showed a frenetic scene as a row of bicycle police clad in riot gear threw the concussive devices into the crowd, sending many scattering.
The Seattle Times
newspaper said the protesters had gathered around 6 p.m. local time after a peaceful march on immigration.