KOIN 6 NEWS - Counter-demonstrators march through downtown Portland on Sunday.

Police report that two officers were injured and seven people arrested by early afternoon. Police said they faced projectiles. They deployed at least one flash-bang device and pepper spray to disperse groups.

Before that, tensions flared in Tom McCall Waterfront Park on Sunday as a handful of demonstrations carrying American flags faced off against hundreds of counter-demonstrators, many dressed in black with the faces covered and chanting anti-fascist slogans.

The scene was just north of Salmon Springs Fountain, which conservative activist Joey Gibson of the Patriot Prayer organized had previously announced he would hold a large rally at 2 p.m. on Sept. 10. But Gibson switched the location to Vancouver on Satursday, although he said the "inner circle" of his organization would still appear near the waterfront in Portland.

Some of that group may have driven past the large group of counter-demonstrators in two Chevy pickups around 1 p.m. Both carried men dressed in dark clothes in the cabs and beds. A combined American-Confederate flag flew from the bed of the lead truck, a white Chevy Avalanche. It was not immediately clear if Gibson or any of his followers were in the trucks, however, because they did not stop but drove past the crowd to jeers and obscene gestures from those who saw them.

KOIN 6 NEWS - Patriot Prayer organizer Joey Gibson at the Vancouver rally on Sunday

The Vancouver rally took place at the Port of Vancouver amphitheater on the Columbia River. Although some counter-demonstrators showed up, dozens of police stood between them and the Patriot Prayer ralliers. Neither group got close to the other, speeches were made, chants were yelled and the event ended with a round of media interviews.

Portland police were assisted by the Oregon State Police, the Multnomah County Sheriff's Office, the Federal Protective Service, the Multnomah County District Attorney's Office, and Portland Fire & Rescue.

KOIN 6 News is a news partner of the Portland Tribune and contributed to this story.