Donald Trump has pledged there will be an orderly transition after the US Congress formally validated Joe Biden's presidential election victory on a day that saw a time-honoured ceremony become a nightmare of unprecedented political terror.
The House and Senate certified the Democrat's electoral college win early on Thursday after a violent throng of pro-Trump rioters spent hours on Wednesday running rampant through the Capitol.
A woman was fatally shot, windows were smashed and the mob forced shaken legislators and aides to flee the building, shielded by Capitol police.
Mr Trump said in a statement tweeted by his social media director Dan Scavino: "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."
The rampage began shortly after Mr Trump repeated his unfounded claims of election fraud to thousands of rallying demonstrators he had invited to Washington. Many then surged to the Capitol after he incited them to go there as legislators debated the electoral votes.
More than six hours after the violence erupted, members resumed the session.
Thirteen Republican senators and dozens of party representatives had planned to force debate and votes on the ballots in up to six states.
The assault on the Capitol made some Republicans squeamish about trying to overturn Mr Biden's win, and challenges were lodged only against Arizona and Pennsylvania. Both efforts lost overwhelmingly.
Mr Biden defeated Mr Trump by 306-232 electoral votes and will be inaugurated on January 20.
A number of White House aides were discussing a potential mass resignation, according to people familiar with the conversation.
Stephanie Grisham, the first lady's chief of staff and a former White House press secretary, submitted her resignation yesterday.
Deputy national security adviser Matt Pottinger, White House social secretary Rickie Niceta and deputy press secretary Sarah Matthews also resigned, according to officials.
More departures were expected in the coming days, officials said.
Other aides indicated they planned to stay to help smooth the transition to the Biden administration.
And some harboured concerns about what Mr Trump might do in his final two weeks in office if they were not there to serve as guardrails when so few remain.
Mr Trump's begrudging statement acknowledging defeat came after even longtime allies floated whether members of his Cabinet should invoke the 25th Amendment and remove him from office.
Former New Jersey governor Chris Christie told ABC that "responsible members of the Cabinet" should be thinking about fulfilling their oath of office, adding that Mr Trump had "violated his oath and betrayed the American people".
Mr Trump has been single-mindedly focused on his electoral defeat since Election Day, aides said, at the expense of the other responsibilities of his office, including the fight against the raging coronavirus.
Indeed, it was Vice-President Mike Pence, not Mr Trump, who spoke with the acting defence secretary to discuss mobilising the DC National Guard on Wednesday afternoon.
Hours earlier, Mr Trump had appeared at a massive rally near the White House, where he continued to urge supporters to fight the election results and encouraged them to march to the Capitol in remarks that were peppered with incendiary language and rife with violent undertones.
At one point, he even suggested he might join them - a prospect that was discussed by the White House but eventually abandoned.
"We're going to the Capitol," he said.
"We're going to try and give our Republicans ... the kind of pride and boldness that they need to take back our country."
Earlier in the rally, his lawyer, Rudy Giuliani, had advocated what he had called "trial by combat".
As the violence raged, Republican politicians and former administration officials had begged Mr Trump to tell his supporters to stand down.
