According to a White House staffer, then-US President Donald Trump and close associates were aware of the potential violence on January 6, 2021.
Cassidy Hutchinson said at a public hearing by the investigative committee into the Capitol attack on Tuesday that Trump was aware of the guns in the audience before speaking to his supporters that day.
Hutchinson worked in the White House for Trump's then-Chief of Staff Mark Meadows.
"I don't care if they have guns - they're not here to hurt me.
You can march to the Capitol from here.
Take away the damn metal detectors," Cassidy quoted Trump as saying.
She claimed to have heard these words from him shortly before his speech.
When a president makes a speech, security personnel require those present to pass through metal detectors.
The committee of inquiry learned from law enforcement reports that participants at the Trump rally had pepper spray, knives, brass knuckles, tasers and blunt objects, said committee vice chair Liz Cheney.
According to Hutchinson, Meadows was also informed - but showed almost no reaction.
White House Counsel Pat Cipollone urged her on Jan. 3 to lobby Meadows to prevent a protest, Hutchinson said.
"We'll be charged with every crime imaginable if we start this movement," he reportedly told her.
On January 6, 2021, Trump supporters violently stormed the seat of parliament in the capital Washington.
Congress met there to certify Biden's election victory.
Five people were killed in the riots, including a police officer.
The attack on the heart of US democracy shook the country.
Trump had recently incited his supporters at a rally that his election victory had been stolen.