A demonstration in support of the Civil Rights Rights of the Second Constitutional Treaty drew protesters on Saturday in Seattle, forcing dozens of police to separate the two parties.
Conservative groups Washington 3 Percenters and Patriot Prayer held their "Liberty or Death" rally outside Seattle City Hall to fight a city-based anti-gun violence initiative while a group of left-wing organizations gathered nearby.
The Left – including members of the Workers Solidarity, Radical Women and Freedom Socialist Party – shouted and used cowbells and sirens to drown speeches from the other side.
An armed gunman wearing a Donald Trump hat was treated for a crime on the scene. A police spokesman told the Seattle Times that a total of three men had been arrested for misdemeanors.
As tensions increased, additional police arrived, including some in combat gear. Bicycle police set up their bicycles as a kind of mobile barrier to keep protesters from entering the street.
The Weapons Control Initiative would extend background checks, increasing the age from 18 to 21 for the purchase of semi-automatic rifles, and establish standards for the safekeeping of firearms
On Friday, a judge handed down 300,000 signatures, which were necessary Election campaign in November on the grounds that the electoral rules were not met. The Alliance for Weapons Stewardship, the group behind the proposal, has appealed against the motion.
Saturday's protest came two weeks after the police in Riot, Portland, Oregon, attempted to separate right and left groups. The effort was largely successful, but the police were accused of being cumbersome, prompting the city's new police chief to order a review of the use of force by officers.
The Associated Press contributed to this report.