Video report by ITV News Washington Correspondent Robert Moore
President Donald Trump has committed to an "orderly transition" of power to President-elect Joe Biden as the world reels from the scenes of chaos in the Capitol on Wednesday.
Despite rioting from Trump supporters, Congress worked through the night to approve the US election result.
Shortly after the tally was announced, President Trump issue his statement but warned that "it’s only the beginning of our fight to Make America Great Again".
Senators resumed business in Congress just hours after rioting Trump supporters stormed the Capitol.
Four people died, including a woman shot by police inside the building. Three others died from "medical emergencies". Fifty-two people were arrested.
Fired up by the president's false allegations that November's election was "stolen" and "rigged", hundreds of Trump supporters fought police and stormed the home of America's federal government.
Once inside rioters chanted "stop the steal", paraded through the halls with confederate flags, and forced police to retreat to the upper floors of the building.
There was no evidence of widespread voter fraud in the 2020 US election, and nearly all the legal challenges from Trump and his allies have been dismissed by judges.
Mr Trump said there "will be an orderly transition on January 20" but again refused to concede the election.
In a statement released by his deputy chief of staff Dan Scavino, Mr Trump said: "Even though I totally disagree with the outcome of the election, and the facts bear me out, nevertheless there will be an orderly transition on January 20th.”
“I have always said we would continue our fight to ensure that only legal votes were counted. While this represents the end of the greatest first term in presidential history, it’s only the beginning of our fight to Make America Great Again,” he added.
President Trump's own Twitter, Facebook and Instagram accounts have been temporarily blocked after he addressed rioters who stormed the Capitol.
In a video message, since removed from the social media sites, he said: "We love you, you're all very special".
Washington Correspondent Robert Moore on the fallout of Wednesday's chaos
President Trump's unfounded allegations fanned the flames for thousands of protesters outside the White House early on Wednesday - where he goaded them to march to the Capitol.
Following the aftermath of Wednesday's chaotic scenes, the FBI said it was "seeking to identify individuals instigating violence in Washington, DC" and was "accepting tips and digital media depicting rioting or violence in and around the US Capitol".
Senators were forced to dive for cover and flee Congress as protesters smashed windows and doors to enter the Capitol.
Armed security drew their weapons on rioters who eventually forced their way onto the Senate floor.
It took more than six hours for the crowds to be cleared out of the building in order for US politicians to continue their certification of the electoral college vote.
Amid the chaos, police recovered two pipe bombs, one outside the Democratic National Committee and one outside the Republican National Committee.
They also found a cooler from a vehicle that had a long gun and Molotov cocktail on Capitol grounds.
Rioters turned on members of the media too, with television equipment destroyed as camera operators ran for safety amid harassment from the crowd.
The mayhem had forced the House and Senate to abruptly end the day’s debates and flee to safety under the protection of police.
The events at the Capitol prompted bipartisan outrage, with many lawmakers blaming President Trump for fostering the violence.
Others called for vice-president Mike Pence - who ratified the electoral college vote, despite pressure from Trump to reject it - to remove President Trump from office under the 25th amendment.
Returning to the chamber after the last of the mob had been cleared, VP Pence reopened the Senate and directly addressed the demonstrators: "You did not win."
Leaders from across the world condemned the violence, and criticised President Trump for failing to call an end to it.
Prime Minister Boris Johnson condemned the "disgraceful scenes".
He tweeted: "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."
Political science professor Keneshia Grant on her emotions seeing the Confederate flag raised in the Capitol
The House of Commons Speaker wrote to US Speaker Nancy Pelosi on Thursday - rioters broke into her office and tore down her name plaque from above the door.
Sir Lindsay Hoyle wrote: "I just wanted to express my shock at last night’s events in the Capitol, and to offer you my solidarity against such unprovoked violence."
"Seeing your office trashed in that way and its occupation by one of the rioters was particularly outrageous.
"I am just so relieved you were not hurt, although I can only imagine how violated you must feel after having a protester at your desk."
Reaction in the US was immediate - as the Senate reconvened on Wednesday, Senate Democratic leader Chuck Schumer said President Trump “bears a great deal of the blame” for the actions of the mob, adding the events “did not happen spontaneously”.
Mr Schumer also said January 6 will “live forever in infamy” and will be a stain on the democracy.
He said: “The president, who promoted conspiracy theories that motivated these thugs, the president, who exhorted them to come to our nation’s capital, egged them on.”
Speaker Pelosi said Congress’ certification of President-elect Joe Biden’s election win showed the world it will not back down.
She said: “Despite the shameful actions of today, we will be part of a history that shows the world what America is made of.”
Vice president Mike Pence and Senate majority leader Mitch McConnell broke with their president.
The former claimed America's democracy would enter a "death spiral" if November's election result was not ratified.
Speaking following the resumption of proceedings, Mr Pence condemned the insurrection and warned that "violence never wins".
Republican Senate Majority Leader Mitch McConnell said the “failed insurrection” underscored lawmakers’ duty to finish the count.
Multiple Republican senators have reversed course and now say they will not object to congressional certification of President-elect Joe Biden’s victory.
Watch ITV News Washington Correspondent Robert Moore's report from inside the US Capitol as rioters stormed the building
Senators Steve Daines of Montana, Mike Braun of Indiana and Kelly Loeffler of Georgia all said in light of the violence they would stand down from planned objections to Mr Biden’s win.
Ms Loeffler said that the “violence, the lawlessness, and siege of the halls of Congress” were a “direct attack” on the “sanctity of the American democratic process”.
'Words matter': US Senate chaplain Barry Black closes hearing
All three had previously signed on to Mr Trump’s false claims of widespread voter fraud to explain his defeat.
Both the Senate and the House voted overwhelmingly to reject an objection to Mr Biden’s win in Arizona.
Other objections to results from Georgia, Michigan and Nevada fizzled without adequate support from senators.
An objection to Pennsylvania backed by Republican senators Josh Hawley and Scott Perry forced deliberations, though senators quickly derailed the attempt to overturn the state’s support for the Democrat.
Inside the Washington siege - Robert Moore on his report that shocked the world