Donald Trump urged his supporters on Wednesday night to return to their homes after armed mobs stormed the Capitol building in Washington as lawmakers debated the last rites of his four-year presidency.
Members of the House of Representatives and the Senate who were certifying the victory of Joe Biden in November's election were escorted out of the building as chaos engulfed the chambers
Security officials ordered administrative staff to stay in their offices after police barricades were breached.
As the National Guard arrived at the building, protesters were were seen roaming through the chambers waving flags and taking selfies.
Biden said the scenes bordered on sedition.
"I call on this mob to pull back and allow the work of democracy to go forward," Biden added.
He urged Trump to go on national television to rein in his supporters.
Trump, who has contested the result of the November poll, eventually posted a video on Twitter in which he repeated his claims about election fraud but urged the protesters to leave.
"You have to go home now, we have to have peace," he said.
The unprecedented images from the cradle of American democracy drew worldwide condemnation.
French foreign minister, Jean-Yves Le Drian, said the violence was an attack against democracy.
"I condemn it. The will and the vote of the American people must be respected," he tweeted.
The British prime minister, Boris Johnson, also called for an end to what he denounced as disgraceful scenes.
"The United States stands for democracy around the world and it is now vital that there should be a peaceful and orderly transfer of power,” he tweeted.
The German foreign minister, Heiko Maas, said democracy's enemies would be cheered by the scenes of violence.
"Trump and his supporters must accept the decision of American voters at last and stop trampling on democracy," Maas added.
No place for violence
The US national security advisor, Robert O’Brien said: “Violence has absolutely no place in our democracy.”
Earlier on Wednesday, Democrats won two run-off seats in the state of Georgia to gain the majority in the Senate and give Biden’s party control of the upper and lower houses of congress.
The chaotic scenes bookended a day of mounting tension in the American capital. Trump repeated allegations of fraud during his address to thousands of his supporters on a park near the White House.
"Our country has had enough and we will not take it any more," Trump said.
However election officials from both parties and independent observers have said there was no significant fraud in the 3 November vote.
Weeks have passed since the states completed certifying that Biden won the election by 306 electoral college votes to Trump's 232.
"We will never give up," Trump added. "We will never concede. It doesn't happen. You don't concede when there's theft involved."
Biden will be sworn in as president on 20 January.