Updated June 4, 8:12 a.m.

BY GORDON R. FRIEDMAN AND JIM RYAN

Left- and right-wing protesters demonstrated and sometimes clashed in violent outbursts Sunday evening in downtown Portland, drawing police in riot gear, disrupting traffic and resulting in arrests.

The polar opposites across America's political divide stood on either side of a street in the heart of the city lined with government buildings, shouting insults at each other.

On the political left were members of antifa, a self-described anti-fascist group often clad in black with their faces covered. On the political right were Joey Gibson and followers of his Patriot Prayer group, some who are pro-Trump, others appearing to be mostly anti-antifa. About 300 attended.

Police -- swathed in pads, helmets and shin guards and hanging off special personnel carrier trucks -- clutched wooden batons as they tried to keep protesters on the sidewalks when they left parks near City Hall and started walking.

Authorities stepped in as heated banter between protesters spiraled into occasional fistfights. Several people received first-aid from medics on the scene.

Portland police said officers with the Federal Protective Service and a Multnomah County sheriff's deputy used pepper spray twice, when when protesters fought. Demonstrators used pepper spray too, police said, and some threw fireworks, bottles, rocks and ball bearings at each other.

Blocks away on the waterfront, the Portland Rose Festival carried on undisturbed, with the Ferris wheel turning and music blaring at the event's traditional carnival.

Authorities arrested four men during the clashes. Andrew Arbow, 32, and Jonathan Feit, 36, were booked in the Multnomah County jail on suspicion of disorderly conduct, police said. Bryan Nyman, 26, who was also jailed, faces assault and robbery charges.

Gregory Isaacson, 43, was detained at Terry Schrunk Plaza, cited and later released after police say he failed to comply with a lawful order.

Gibson organized his group's rally as a high-intensity send-off to one of his supporters, but it came nearly a year to the day after similar demonstrations between thousands turned violent at the same location.

The demonstrations last June followed the brutal MAX train attack on May 26. Jeremy Christian, who had himself attended an earlier Patriot Prayer rally in Southeast Portland, is accused of stabbing to death two men on a train and leaving a third, Micah Fletcher, critically injured but alive with a deep neck wound.

Fletcher, bearing a scar from Christian's knife, attended Sunday's gatherings, but stayed far from the melees.

The Police Bureau faces a federal civil rights lawsuit after fierce criticism of its response at last year's dueling protests when they corralled more than 300 people and took their photos.

Police Chief Danielle Outlaw released a statement saying police this time tried "to provide a safe environment for all participants, non-participants and community members while ensuring the peaceful exercise of the First Amendment."

She said police used social media, a loud hailer and one-on-one communication with organizers "to encourage an environment in which Portland community members could safely practice their right to free speech and assembly."

Officers separated and arrested people "on occasions when people's safety were in jeopardy," she said.

-- Gordon R. Friedman

-- Jim Ryan