Thousands of supporters of US President Donald Trump turned out in Washington DC to back his unsubstantiated claims of voter fraud in the election.
Flag-carrying demonstrators were joined by members of far-right groups including the Proud Boys, some wearing helmets and bullet-proof vests.
The largely peaceful demonstration saw some violence later in the evening, as Trump supporters and counter-protesters clashed in several skirmishes.
Joe Biden won the 3 November election.
On Friday, he solidified his victory with a projected win in the state of Georgia – making him the first Democratic candidate to take the state since 1992.
He now has 306 votes in the electoral college – the system the US uses to choose its president – which far exceeds the 270 threshold to win.
However, Mr Trump has so far refused to concede. He has launched a flurry of legal challenges in key states and made unsubstantiated allegations of widespread electoral fraud – but his efforts have so far been unsuccessful.
Mr Trump’s supporters kicked off the demonstrations at about noon local time (17:00 GMT) on Saturday near Freedom Plaza, just east of the White House, and later headed towards the Supreme Court.
As well as more mainstream Trump supporters, members of the far-right Proud Boys and the Oath Keepers militia group were among the marchers. Conspiracy theorist Alex Jones addressed the crowd.
Mr Trump’s motorcade passed the gathering demonstrators on Saturday morning and did a circuit of nearby Freedom Plaza, but he carried on to his golf club in Sterling, Virginia without addressing the crowds.
He later retweeted video of protesters, posted by White House official Dan Scavino, vowing “We will WIN!”
While the daytime event was largely orderly, Trump supporters clashed with counter-demonstrators in the night. Video footage posted on social media showed fights breaking out.
Officials said 20 people had been arrested on a variety of charges, including assault and weapons possession. One stabbing was reported. Two police officers were also injured.
The president continues to dispute the election result. In a slew of tweets on Saturday, he said checks on ballots in Georgia were a “waste of time”, alleging problems with signatures but without giving evidence.
A manual recount is to be carried out in Georgia because of the narrow margin between the two candidates, but this is not expected to change the results there.
On Friday, election officials said the vote was the “most secure in American history”, the most direct rebuttal from federal and state authorities of the president’s claims.
On Friday, White House spokeswoman Kayleigh McEnany told Fox News: “President Trump believes he will be President Trump, have a second term.”