Violence broke out in downtown Portland, Oregon, on Sunday as Antifa activists stormed a Patriot Prayer rally — about a year after similar dueling rallies triggered bloody fights and arrests.

Some protesters on Sunday hurled bottles and fireworks at police officers while others were caught with knives and other weapons, Portland Police tweeted. Officials encouraged people to get out of the immediate area "for their safety."

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Many of the Antifa activists wore black and covered their faces. Some protesters said they were demonstrating against police brutality; one sign bluntly read "F--- the police."

Patriot Prayer, which bills itself as a peaceful First Amendment advocacy group, organized a rally — "Tiny's Freedom March," a going-away event for Tusitala John Toese, who's close with group leader Joey Gibson — for 5 p.m.

The Rose City Antifa scheduled a counter-protest for 4 p.m. "to show Patriot Prayer, just as we showed them last year, that their violence and hatred has no place in Portland."

The demonstrations came a year after the same two groups converged in downtown Portland for opposing rallies, KOIN reported. Last year's protests resulted in 14 arrests.

Police said Sunday that while the city respects "the right to assemble," anyone with weapons or anyone involved in violent activities was subject to arrest.

It was not immediately clear if Sunday's demonstrations downtown resulted in any arrests, but photos and videos posted to social media showed protesters fighting and clashing, while some apparently were doused with pepper spray.