US President-elect Joe Biden has blasted the “insurrection” of pro-Trump rioters who stormed the US Capitol and he demanded an end to their “siege”.
The Democrat called on outgoing President Donald Trump to “step up” and repudiate the violence.
In a tweeted video, Mr Trump repeated debunked claims the vote was “stolen”, but urged protesters to “go home”.
A joint session of Congress confirming electoral college votes has been suspended and forced into recess.
What did Biden say?
Mr Biden said: “I call on President Trump to go on national television now to fulfil his oath and defend the Constitution and demand an end to this siege.
“To storm the Capitol, to smash windows, to occupy offices on the floor of the United States Senate, rummaging through desks, on the House of Representatives, threatening the safety of duly elected officials.
“It’s not protest; it’s insurrection.”
What did Trump say?
Mr Trump responded in a recorded video on Twitter, repeating his unproven claims of fraud in November’s White House election.
“I know your pain. I know you’re hurt,” said the Republican president, who leaves office on 20 January.
“We had an election that was stolen from us. It was a landslide election, and everyone knows it, especially the other side.
“But you have to go home now. We have to have peace.”
Twitter added a warning label to the tweet, citing the disputed claim of election fraud and “risk of violence”.
What’s happening at the Capitol?
There have been reports of guns drawn in the building and at least one person shot.
A woman was reported to be in a critical condition after receiving a neck injury.
There has been an armed confrontation at the doors of the House of Representatives.
Tear gas has also been used.
Members of Congress have been told to evacuate the building or remain where they are. One congresswoman tweeted that she was staying in her office.
Vice-President Mike Pence called on the rioters to leave the Capitol immediately, saying the violence and destruction “must stop now”.
Rioters were seen marching through the building chanting “We want Trump” and one was photographed in the Senate president’s chair.
A citywide curfew has been declared from 18:00 to 06:00 (23:00 to 11:00 GMT) by Washington DC’s mayor.
There are also reports of protests at state legislatures in Kansas and Georgia.
‘Surrender the building to us’
By Laura Trevelyan, BBC News, Washington
On the steps of Capitol Hill, hundreds of loyal Trump supporters are packed closely together, as nearby armed police officers keep a watchful eye.
The mood here is tense and defiant.
“We’re not [expletive] Antifa!” one man screams at the police, referring to the loose coalition of “anti-fascist” activists that oppose Mr Trump.
Trump loyalists near him wave placards that say “show us the ballots”.
“All we want is for the Capitol police to stand down, and surrender the building to us,” says one man to news cameras, as he is filmed by other Trump supporters.
The conviction here is that the election was stolen from President Trump, and the lawmakers inside the building should do their duty and somehow award the election to him.
Never mind that election officials have certified the results and the courts have thrown out Trump campaign lawsuits alleging fraud because there’s no evidence.
It’s a siege mentality here, as word spreads through the crowd that the National Guard is on its way to the Capitol.
What were the protesters targeting?
A joint session of Congress was being held to certify Mr Biden’s election victory on 3 November.
The proceedings are usually brief and ceremonial but Republican lawmakers have been objecting to some results.
For days Mr Trump had also been putting pressure on Mr Pence, who is presiding over the session, to block certification of the result.
But in a letter to Congress on Wednesday, Mr Pence said that he had no “unilateral authority to decide which electoral votes should be counted”.
The protesters marched on the Capitol from a “Save America Rally”, where Mr Trump had urged them to support those legislators opposing Mr Biden’s confirmation.
Mr Trump, who has refused to concede the 3 November election, said earlier on Wednesday: “We will never give up. We will never concede.”
He has also tried to throw doubt on the integrity of Tuesday’s Senate run-off votes in the southern, traditionally Republican, state of Georgia – where two Democrats are projected to have won.
If the Democrats win both they will gain effective control of the Senate – something that will help Mr Biden push forward his agenda after he is inaugurated as president on 20 January.