An 'armed standoff' is currently ongoing in the US Capitol building – America's equivalent to the Houses of Parliament – after supporters of outgoing President Donald Trump stormed the building.
A woman has been shot in the chest during the violent invasion which began when hundreds of protesters marched on the Capitol for a rally.
Later on on Wednesday, US media outlets were reporting the woman had died of her injuries, citing police sources.
Images circulating on social media appear to show a woman with a serious injury to her neck being carried out of the building.
A bomb was found outside the Republican National Committee headquarters and multiple officers have been wounded as riot police descend on the building.
President-elect Joe Biden has condemned the scenes, saying democracy is "under an unprecedented assault...unlike anything we've seen in modern times".
"An assault on the citadel of liberty, the Capitol itself," he said.
"An assault on the people's representatives and the Capitol Hill police, sworn to protect them. And the public servants who work at the heart of our Republic... Let me be very clear. The scenes of chaos at the Capitol do not reflect a true America."
President Trump himself has recorded a bizarre video addressing the rioters in which he says "we love you, you're very special" and repeats his false claim he won last November's election in a "landslide".
Reporters on the scene described an armed stand-off at the door to the US House Chamber inside the Capitol, with guns drawn.
Politicians who were gathered inside the Senate to certify Joe Biden's 2020 election win were forced to flee as heavily armed protesters barged their way in.
Footage and images uploaded to social media show protesters wandering around inside the evacuated Senate chamber, while others snapped photos of themselves inside the offices of major politicians including Nancy Pelosi.
The Senate floor has since been cleared of rioters and police have regained control of the area, CNN reports.
President Trump has directed the National Guard and other "federal protective services" to assist with responding to the rioters.
All buildings within the Capitol Complex have now been placed into emergency lockdown, and the mayor of Washington DC has placed a 6pm curfew on the city.
US Capitol Police have evacuated two buildings on the Hill, including the Madison Library of Congress Building and the Cannon House Office Building.
Meanwhile President Trump, who encouraged his supporters to march on the Capitol at a rally today, has tweeted asking the protesters to remain peaceful.
"I am asking for everyone at the U.S. Capitol to remain peaceful," he said.
"No violence! Remember, WE are the Party of Law & Order – respect the Law and our great men and women in Blue. Thank you!"
Boris Johnson has condemned the "disgraceful scenes", saying: "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."
Hundreds of people wearing Trump's signature MAGA merchandise and military gear showed up at the March to Save America rally, according to eye witnesses at the scene.
Many of them reportedly belonged to far-right organisation the Proud Boys, which has a history of violent events.
Trump has been fanning the fury of his supporters for weeks by insisting the 2020 election was stolen from him despite no evidence to support this claim.