• A woman has died of a gunshot wound and police officers have been injured after supporters of President Donald Trump stormed the US Capitol Building.
• President-elect Joe Biden called on Trump to demand an end to the siege and in a message released on Twitter, Trump told protesters: "Go home, we love you".
• The US Capitol Building is now secure and lawmakers are continuing with certification of the Electoral College.
• Tear gas was deployed after mobs broke in and protesters were seen sitting at the desk of Speaker of the House Nancy Pelosi. Members of the House and media took cover in the chambers.
• Democrat Jon Ossoff has won his Senate runoff race in Georgia against David Perdue, giving Democrats effective control of the Senate and allowing Biden to pursue his agenda.
• Twitter has begun removing Trump tweets in their entirety and have locked the President out of his account for 12 hours.
Former presidents have savaged Donald Trump for inciting today's deadly rioting at Capitol Hill, with Bill Clinton pleading for a peaceful transfer of power to the new Biden administration.
Clinton said the "unprecedented assault on our Capitol, our Constitution, and our country" was fuelled by "more than four years of poison politics spreading deliberate misinformation, sowing distrust in our system, and pitting Americans against one another".
He added: "The match was lit by Donald Trump and his most ardent enablers, including many in Congress, to overturn the results of an election he lost."
Former President Barack Obama implored Republicans to "choose reality and take the first steps toward extinguishing the flames".
"History will rightly remember today's violence at the Capitol, incited by a sitting president who has continued to baselessly lie about the outcome of a lawful election, as a moment of great dishonour and shame for our nation. But we'd be kidding ourselves if we treated it as a total surprise.
"I've been heartened to see many members of the President's party speak up forcefully today. Their voices add to the examples of Republican state and local election officials in states like Georgia who've refused to be intimidated and have discharged their duties honourably.
"We need more leaders like these — right now and in the days, weeks, and months ahead as President-elect Biden works to restore a common purpose to our politics. It's up to all of us as Americans, regardless of party, to support him in that goal."
The mob of protesters made its way into the US Capitol earlier today, forcing police to evacuate lawmakers and delaying the constitutional process to affirm President-elect Joe Biden's victory in the November election. Violent clashes between protesters and police took place throughout the day before riot police dispersed the crowds with tear gas.
Authorities say the Capitol Building is now secure and police have begun moving protesters along after a 12-hour curfew kicked in across Washington DC. A woman shot in the day's chaos has since died of her injuries.
Trump's provocative tweet
Trump, in a tweet since removed by Twitter, offered a controversial justification for the siege: "these are the things and events that happen when a sacred landslide election victory is so unceremoniously & viciously stripped away from great patriots who have been badly and unfairly treated for so long".
"Go home with love & peace. Remember this day forever," Trump wrote.
The President earlier called on his supporters to leave the Capitol but continued to falsely claim the election had been stolen from him. That video, posted on Twitter, has since been removed by the social media site, which has also locked the President's account for 12 hours following "violations of our civic integrity policy".
NZ Prime Minister Jacinda Ardern responded to the day's events on social media.
"Like so many others, I've been watching what's happening in the United States. I share the sentiment of friends in the US - what is happening is wrong," she wrote.
"Democracy - the right of people to exercise a vote, have their voice heard and then have that decision upheld peacefully should never be undone by a mob. Our thoughts are with everyone who is as devastated as we are by the events of today. I have no doubt democracy will prevail."
Biden blasts chaos: 'Borders on sedition'
President-elect Joe Biden said the protesters do not represent America and that the invasion of the Capitol "borders on chaos, borders on sedition".
The siege took place as results from the Georgia Senate run-offs confirmed two Democrats had been elected, giving Democrats effective control of the legislative branch and allowing Biden to pursue a more ambitious agenda.
The protesters aimed at thwarting the peaceful transfer of power and forced lawmakers to be rushed from the building, putting a halt to the certification of Biden's Electoral College win.
The joint session of Congress has now resumed.
The ordinarily mundane procedure of certifying a new president was always going to be extraordinary, with Republican supporters of Trump vowing to challenge the results of an election that they have baselessly insisted was reversed by fraud. But the "Trump March" protest soon overshadowed everything.
In raucous, out-of-control scenes, protesters fought past police and breached the Capitol Building, shouting and waving Trump and American flags as they marched through the halls.
The protesters abruptly interrupted the congressional proceedings in an eerie scene that featured official warnings directing people to duck under their seats for cover and put on gas masks after tear gas was used and police barricaded the House of Representatives.
Lawmakers paused their vote on certifying Biden's Electoral College win and evacuated the chamber. Protesters continued trying to break down the door of the House.
While police guarded the House of Representatives, protesters took over other parts of the Capitol Building.
As the situation devolved, President Donald Trump called on his supporters to remain peaceful, writing on Twitter: "No violence! Remember, WE are the Party of Law & Order".
The siege has been almost universally condemned by lawmakers and officials.
Republican Senator Mitt Romney reportedly excoriated his colleagues in the Senate as chaos erupted in the chamber, the Huffington Post reported.
"This is what you've gotten, guys," he yelled, seemingly addressing his GOP colleagues who've pushed Trump's election fraud claims.
Tom Bossert, Trump's ex-homeland security adviser, says the outgoing president is responsible for the siege.
"The President undermined American democracy baselessly for months. As a result, he's culpable for this siege, and an utter disgrace," Bossert wrote on Twitter.
Republican Senator Richard Burr of North Carolina also directly blamed Trump for the violence.
"The President bears responsibility for today's events by promoting the unfounded conspiracy theories that have led to this point. It is past time to accept the will of American voters and to allow our nation to move forward," he said in a statement.
Former President George W Bush wrote in a statement that he was "watching the scenes of mayhem unfolding at the seat of our Nation's government in disbelief and dismay ... This is how election results are disputed in a banana republic – not our democratic republic."
Bush said the "insurrection" was sparked by "people whose passions have been inflamed by falsehoods and false hopes". He called on those who were disappointed by the results of the presidential election to put country over politics and let elected officials do their job.
Stephanie Grisham, the former White House communications director and press secretary, has now resigned due to today's protests, CNN reports.
Earlier in the day, in a wide-ranging speech, President Donald Trump denounced the November presidential election as a fraud and vowed to never concede. The President said he was winning the race until "explosions of bulls***" turned the results in Biden's favour.
"We will never give up, we will never concede," he said, to cheers and hollering. "We will stop the steal.
"Our country has had enough, we will not take it any more."
The speech prompted protesters to rush towards the Capitol. DC police stood guard against the charging crowd but could not hold back the tide.
Hundreds scaled and kicked aside the barricades, yelling "forward!" as they ran ahead.
The Washington Post have also reported two "realistic-looking" homemade bombs were found near the Republican National Committee headquarters and the Democratic National Committee headquarters in downtown Washington.
The suspected bomb outside the RNC was found next to a trash container, and was a metal pipe with wires running from inside the pipe to a plastic kitchen timer.
FBI said in a statement said that explosives experts responded to both devices, and they were "rendered safe by the FBI and our law enforcement partners".
In a statement, the RNC called the suspicious package outside their building an "explosive device that was successfully detonated."
Violence was not contained to the capital, with protests erupting around the country.
Trump supporters in Los Angeles were seen clashing with counter protesters.
Protesters outside the Capitol Building also attacked a news media crew.
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Congress yet to affirm Biden's win
Before the siege, Vice President Mike Pence and the Members of the Senate were admitted into the House Chamber to meet with the House of Representatives in a Joint Session to certify the Electoral College ballot count.
Pence had already issued a statement by the time the Congress met, declaring he would not intervene in the electoral count and killing hope of Congress overturning Biden's win.
Starting with the state of Alabama, the tellers began announcing the results of the Electoral College balloting, but this was halted when Republicans objected to the election tally in Arizona.
The objection to the Arizona count forces two hours of debate in the House and Senate, sending lawmakers away to separate deliberations.
All challenges are ultimately doomed to fail, since both chambers of the Congress would need to sustain any objection, and Democrats control the House of Representatives.
Senate Majority Leader Mitch McConnell has repeatedly voiced opposition to the prospect of Republicans challenging the Electoral College and today said American democracy was under threat.
Nevertheless, Trump called on his Vice President to refuse to certify the vote. "All he has to do is nothing, sometimes the most courageous thing to do is nothing.
"I hope Mike is going to do the right thing. I hope so, I hope so, because if Mike Pence does the right thing, we win the election," Trump said.
"All Vice President Pence has to do is send it back to the states to recertify and we become president and you are the happiest people.
"If he doesn't, then that will be a sad day for our country."
However, Pence said he would refuse to do so, saying he could not claim "unilateral authority" to reject electoral votes that would make Biden president.
Pence's statement read: "my oath to support and defend the Constitution constrains me from claiming unilateral authority to determine which electoral votes should be counted and which should not".
Trump later responded, denouncing his own Vice President.
Georgia's Senate runoff elections
Democrats have now won both Georgia Senate seats — and with them, the US Senate majority, serving Trump a stunning defeat in his last days in office.
Jon Ossoff and Raphael Warnock, Democratic challengers who represented the diversity of their party's evolving coalition, defeated Republicans David Perdue and Kelly Loeffler two months after Biden became the first Democratic presidential candidate to carry the state since 1992.
Their success is a symbol of a striking shift in Georgia's politics as the swelling number of diverse, college-educated voters flex their power in the heart of the Deep South.
In his speech today, Trump labelled the Georgia runoff elections a "set up", baselessly alleging that voting machines manipulated the results.