Politicians and reporters are trapped inside the US Capitol as a large group of Donald Trump supporters have broken into the building.
Alarming footage and images posted to social media shows protesters wearing MAGA hats and T-shirts grappling with armed police officers outside the Washington DC building.
There have been unconfirmed reports of "suspicious" packages or other items being found at the scene, as well as reports of gunfire and the discovery of a potential pipe bomb.
Protesters are now attempting to break through the barricades surrounding the building which houses both the House of Representatives and the Senate and is currently full of politicians, staffers and journalists.
Photos show a small number of protesters appear to have entered the premises.
All buildings within the Capitol Complex have now been placed into emergency lockdown and the Senate has recessed.
US Capitol Police have evacuated two buildings on the Hill, including the Madison Library of Congress Building and the Cannon House Office Building.
Meanwhile those in the Senate area are trapped inside hoping the police will be able to keep the armed protesters out.
Reporters in the press gallery were reportedly told that if protesters successfully storm the building, they will be rushed into the Senate chamber with the door locked behind them.
Vice-President Mike Pence is among those "sheltering in place" according to reports on Twitter.
The outgoing President Trump had earlier instructed his supporters to march from the White House toward the Capitol to protest his election loss which will see him leave office later this month.
"We're going to try and give our Republicans — the weak ones because the strong ones don't need any of our help — we're going to try and give them the kind of pride and boldness that they need to take back our country," he said.
"So let's walk down Pennsylvania Avenue."
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 the 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.
Local police had beefed up security as a precaution and warned locals to steer clear of potentially violent protesters.
"I just had to evacuate my office because of a pipe bomb reported outside," congresswoman Elaine Luria tweeted.
"Supporters of the President are trying to force their way into the Capitol and I can hear what sounds like multiple gunshots.
"I don't recognise our country today and the members of Congress who have supported this anarchy do not deserve to represent their fellow Americans."
The violence comes just as Republicans seemed to finally offer to work alongside Democrats in the incoming Biden administration after weeks of refusing to engage in the transition process.