"Officials declined to discuss whether the people arrested — on charges including disorderly conduct and unlawful use of a weapon — were affiliated with right-wing groups or with Antifa."

13 were arrested, according to "Portland Protests: Far-Right Groups and Antifa Face Off as Trump Weighs In/Conservative groups are urging the United States to label Antifa a domestic terrorist group. President Trump said the city was “being watched very closely" (NYT). I'm pretty sure right-wingers will assume that those arrested were Antifa, that the Portland police wouldn't have declined to discuss it if they'd arrested Proud Boys. But maybe it's the city's policy to refrain from purporting to know the politics of individuals arrested for disorderly conduct.

On Saturday, a few confrontations broke out in the park as the rally began, but the far-right groups eventually moved behind a police line and were separated from the counterprotesters by a wide gap that officers worked aggressively to maintain.... At least two of those walking with the militia members appeared to have been hit with white substances resembling milkshakes.... Officers intervened in occasional skirmishes at or near the park and seized a stun gun, bear spray, a shield, and metal and wooden poles from the protesters, the police said..... The rally itself was largely uneventful. But more fights broke out after the groups had dispersed and roved the downtown streets in smaller packs, with tense and sometimes bloody exchanges flaring up between demonstrators....