Several hundred Joe Biden supporters rallied near the White House Tuesday, but by nightfall a festive atmosphere was giving way to nervous tension as people fixed their attention on giant screens showing disappointing early results.
As a succession of battleground states fell to President Donald Trump, Democratic party voters in the overwhelmingly blue capital Washington put on brave faces and said they were preparing to dig in for a long haul.
Biden says believes he is 'on track' to win US election.
"We wanted to come out to support Joe Biden and Kamala Harris, hoping for a celebration," said Tammi Girgenti, a 51-year-old retired government official, adding: "I'm a little disappointed with Florida, that's my home state."
"I'm feeling okay, a little bit nervous and a little apprehensive, but I think Biden can squeeze it out by the end of the night or tomorrow or the next day," she laughed.
Biden seemed to be up in Arizona, which Trump won in 2016, but was trailing in other hotly contested states including Pennsylvania, as the race seemed destined to stretch on while votes were counted.
Jake, a 22-year-old student who came with a group of friends, summed up their mood: "We're not feeling too good, but I know that the mail-in the early voting was always going to be kind of later... I think that Biden can still pull it off."
Starting from the afternoon, crowds had converged on a two-block-long stretch of road recently named Black Lives Matter Plaza by the mayor of Washington, which was the focal point of opposition to Trump during racial justice protests over summer.
Others filled the nearby McPherson Square park after the traditional area for such gatherings, Lafayette Square, was shut off by a perimeter fence that went up some weeks ago.
Supporters of the president were a rare sight, but when one appeared and expressed their views, they were quickly swarmed by Biden followers who wanted to debate them.
What appeared to be internal scuffles broke out when members of the far-left Antifa group arrived in the area around midnight.
Wearing all black and carrying black umbrellas, they launched fireworks into the air then marched through the boarded-up downtown area, shouting anti-racism and anti-police slogans and setting fire to some trash cans.
Police on bicycles and in cars escorted the march at a distance from the front and the back, but did not attempt to engage the demonstrators.
The palpable tension of the night was in stark contrast to the calm, cautious optimism of the day when some Biden supporters made bullish predictions and were in the mood to celebrate.
Ruby Estoy, 40, and her friend Concetta Leanza, 34, together with Leanza's terrier Hercules came from Florida on Sunday.
"We came here just to feel the energy and to be here, and to really make sure that our voices get heard," said Estoy.
Another pair of friends, Susan Ryan and Lauren Sanders of New York, said that they were hoping to celebrate.
But "we also are not going to leave the streets, until we know that Donald Trump is going to agree to go peacefully," said Sanders, 55.
First time voter Greta Jones, from Maryland, was bopping along to a go-go band set up in a truck on the street.
"I'm here to show a united front, I voted for Biden and Harris," said the 20-year-old grocery store worker.
Asked how she was feeling about the final result, Jones said: "Honestly I'm scared because either way it's going to be a civil war, and I'm not mentally prepared for that."
