Former US president Donald Trump tried to take the steering wheel from his Secret Service limousine driver in an attempt to join the crowd marching on the US Capitol last year, a top aide in his administration testified today.

Mr Trump got into his car after addressing a rally near the White House, Cassidy Hutchinson told a congressional panel.

He was told he couldn't be with his supporters who were gathering ahead of the protest at the Capitol that turned into a deadly insurrection.

"I'm the effing president, take me up to the Capitol now," Mr Trump said, according to Cassidy Hutchinson, who said the story was relayed to her by another White House official.

Ms Hutchinson was giving evidence before the US committee probing the 6 January, 2021 attack on the Washington DC Capitol building.

She has been an executive assistant to then President Trump's chief of staff Mark Meadows and was a central figure in the White House around the period of the insurrection last year.

White House counsel Pat Cipollone had voiced legal concerns about Mr Trump marching to the Capitol alongside his supporters, Ms Hutchinson said.

"We're going to get charged with every crime imaginable if we make that happen," she recalled Mr Cipollone warning.

Cassidy Hutchinson, a top aide to former White House Chief of Staff Mark Meadows, testifies during to the House Select Committee today

In some of the most explosive testimony from the hearings so far, Ms Hutchinson said Donald Trump and some of his top lieutenants were aware of the possibility of violence ahead of the attack - contradicting claims that the assault was spontaneous and had nothing to do with the administration.

She said she recalled her boss saying four days before the insurrection: "Things might get real, real bad on 6 January."

Ms Hutchinson had sought out Mr Meadows, she said, after a White House meeting involving Mr Trump's lawyer Rudy Giuliani.

As they were heading to Mr Giuliani's car, he asked her if she was "excited" for January 6, she testified.

When she asked what was happening on that day, Ms Hutchinson testified that Mr Giuliani "responded something to the effect of, 'We're going to the Capitol,'" she said.

"'It's going to be great. The president's going to be there. He's going to look powerful. He's going to be with the members. He's going to be with the senators. Talk to the chief about it. Talk to the chief about it. He knows about it.'"

She told Mark Meadows what Mr Giuliani had said, she testified.

"He didn't look up from his phone and said something to the effect of, 'There's a lot going on, Cass, but I don't know. Things might get real, real bad on January 6,'" Ms Hutchinson told the hearing.

"When hearing Rudy's take ... and then Mark's response, that was the first moment that I remember feeling scared and nervous for what could happen on January 6," she added.

Cassidy Hutchinson leaves after testifying during sixth hearing by the US House Select Committee

Ms Hutchinson told the committee that she heard the names of far right groups the Oath Keepers and Proud Boys discussed in the White House as the date approached.

Vice chair Liz Cheney said the committee had obtained police reports that people at the Trump rally had knives, Tasers, pepper spray and blunt objects that could be used as weapons.

Police transmissions played at the hearing showed that others outside the rally had firearms including AR-15 semi-automatic rifles.

Ms Hutchinson has already been the source of several blockbuster revelations, appearing in videotaped depositions at two previous hearings and memorably naming a group of House Republicans who sought pardons from Trump following the violence.

She was also in contact with officials in the battleground state of Georgia, where President Trump infamously pressured officials to "find" enough votes to overcome Joe Biden's victory margin in a phone call that is the subject of a criminal probe.

It was Ms Hutchinson, according to CNN, who told the select committee that Donald Trump voiced approval for the "hang Mike Pence" chants from rioters at the Capitol - an allegation that was among the many eye-popping claims to come out of the opening hearing on 9 June last.

Mr Meadows himself has refused to testify before the panel since handing over thousands of text messages and other documents in the early stages of the investigation.

The House of Representatives held Mr Meadows in contempt in December but the Justice Department decided not to charge him.

The US House Select Committee hearing to investigate 6 January attack continued today

Testimony at the committee's five prior hearings has shown how the Republican former President riled thousands of supporters with false claims that he lost the 2020 election to Democrat Joe Biden because of massive voter fraud.

The committee had said last week it would only reconvene publicly in July but announced a change of plans yesterday, a mere 24 hours before the start of today's hearing.

Donald Trump, who is publicly flirting with another White House run in 2024, denies wrongdoing and accuses the committee of engaging in a political witch hunt.

He has levelled harsh criticism particularly at Representative Liz Cheney, one of just two Republicans on the nine-member committee.

A Reuters/Ipsos poll early this month suggested that about two-thirds of US Republicans believed Mr Trump's false election fraud claims.

The committee, sometime next month, is expected to hold one or two hearings on possible coordination of the 6 January attack by right-wing extremist groups.

During the assault on the Capitol, thousands of Donald Trump supporters smashed windows, fought with police and sent lawmakers, including vice president, Mike Pence, fleeing for their lives.

Four people died the day of the attack, one fatally shot by police and the others of natural causes.

More than 100 police officers were injured, and one died the next day. Four officers later died by suicide