Congressional Democrats are considering impeaching President Donald Trump for a second time, two days after his false claims of election fraud helped encourage a mob that stormed the US Capitol.

Democratic leaders, including House of Representatives Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer, called for immediate impeachment proceedings if Vice-President Mike Pence and Trump’s cabinet refused to take steps to remove him from power.

“The President’s dangerous and seditious acts necessitate his immediate removal from office,” they said in a statement on Thursday evening, accusing Trump of inciting an “insurrection”.

As calls for his removal mounted, Trump released a video in which he denounced the violence that left five people dead.

The Republican president came the closest he has yet to conceding his loss in the November 3 presidential election, promising to ensure a smooth transition to a “new administration”.

President-elect Joe Biden is set to be sworn in on January 20.

Yesterday was not a protest—it was a riot to uphold white supremacy.
(1/8)

— Ben & Jerry's (@benandjerrys) January 7, 2021

Trump’s words were in stark contrast to his speech on Wednesday, when he exhorted a crowd of thousands to descend on the Capitol as Congress met to certify Biden’s victory.

Rioters stormed the building, overwhelming police and forcing authorities to evacuate the House of Representatives and Senate.

A Capitol police officer died from injuries sustained in the assault, the force said late on Thursday.

A female protester was fatally shot by the authorities, and three people died from medical emergencies.

The FBI have offered a reward of up to $US50,000 ($A64,375) for information on people responsible for placing pipe bombs in the headquarters of the two main political parties.

With less than two weeks left in Trump’s term, it is unclear whether enough time remains to complete the impeachment process.

Pelosi has not announced a decision, though she made clear at a news conference that rank-and-file Democrats in her caucus wanted action following Wednesday’s siege.

If impeached in the House, Trump would theoretically face trial in the Republican-controlled Senate, which is scheduled to be in recess until January 19.

Aides to Republican Mitch McConnell, the majority leader, have not said what he would do if the House approved articles of impeachment.

A Trump supporter defiles America’s temple of democracy on Capitol Hill. Photo: Getty

The Democratic-led House impeached Trump in December 2019 for pressuring the president of Ukraine to investigate Biden, but the Republican-held Senate acquitted him in February 2020.

Only two other presidents in history have been impeached, and none has ever been impeached twice.

Democrats will control the Senate after sweeping two runoff elections in Georgia on Tuesday, but the new senators, Jon Ossoff and Raphael Warnock, will not be sworn in until the state certifies the results.

The state deadline to do so is January 22, though it could come sooner.

In Thursday’s video, a flat-toned Trump struck a conciliatory note seldom seen during his presidency, calling for “healing”.

Democrats Nancy Pelosi and Chuck Schumer say Trump must resign or be expelled from the White House. Photo: Getty

As recently as Thursday morning, however, Trump was still claiming the election had been stolen, and he stopped short of acknowledging his loss.

Pelosi and Schumer called on Pence and Trump’s Cabinet to invoke the US Constitution’s 25th Amendment, which allows them to strip the President of his powers if he cannot discharge the duties of his office.
Pence opposes the idea, according to an adviser.

At least two Republicans, Maryland Governor Larry Hogan and US Representative Adam Kinzinger, have said Trump must go.

The Wall Street Journal, seen as a leading voice of the Republican establishment, on Thursday evening called on Trump to resign.

Several high-ranking Trump administration officials have resigned in protest over the invasion of the Capitol, including two Cabinet members: Elaine Chao, the transport secretary who is McConnell’s wife, and Betsy DeVos, the education secretary.

At a news conference to introduce his pick for attorney general, Biden blamed Trump for instigating the attack but did not comment on his possible removal.

-AAP