Demonstrators burnt US flags and marched through Portland, Oregon, singing protest songs and carrying assault rifles as a confusing election night unfolded, through the early hours of Wednesday morning.
The liberal enclave braced for possible clashes after months of divisive rallies involving left-wing activists, right-wing militias and federal officers sent by President Donald Trump's administration.
No violence was reported in the north-western city.
As Mr Trump claimed he won the election early on Wednesday, despite key states still counting ballots, activists gathered outside the federal courthouse in Portland, the centre of the summer's fraught antiracism protests.
"We don't like either candidate. I shamefully voted for Biden, but if Trump gets another four years people will be mad," said a 20-year-old protester, as two American flags were ignited in front of the building.
Many at the courthouse shouted slogans against Mr Trump, while others danced and twerked to loud hip-hop music.
Portland mayor Ted Wheeler was also singled out for abuse, a target of strong dislike for anti-police protesters. Mr Wheeler won re-election on Tuesday.
The FBI gave a warning about the potential for armed clashes in Portland linked to the polls, but there were no signs of election night activity from right-wing groups such as the Proud Boys.
By the early hours of Wednesday police had not engaged with the protesters, 400 of whom participated in a peaceful Black Lives Matter march in east Portland.
The three-hour march was led by a convoy that included at least half a dozen protesters armed with assault rifles, knives and a shotgun. Rumours and reports about the rapidly changing national and state races, in which votes are still being counted, spread among marchers.
"I heard Trump has the momentum now," said protest leader Ty Ford, 20. "It's going to be a riot. Whenever it comes out, it's going to be crazy."
"It is like picking between two evils but honestly, we'll settle with Biden," said fellow leader D D, 22.
Demands included the abolition of the Immigration and Customs Enforcement and justice for black victims of police violence, including George Floyd and Breonna Taylor, before the march ended with a rendition of Hallelujah.
There were also moments of levity as protest leaders cajoled those watching the march from their apartment windows to join the rally.
"Hey, stick your head out the window, tell us how the election is going – and then maybe slip on your shoes and come help us start a revolution," shouted one activist.
