US President Donald Trump has said he will not attend the inauguration of his successor, Joe Biden, on 20 January.
"To all of those who have asked, I will not be going to the Inauguration on January 20th," the president tweeted.
The president-elect welcomed the news, calling Mr Trump's absence "a good thing".
Mr Trump is facing calls for his removal from office after five people died when a mob of his supporters invaded Congress.
The president was not fit to serve in the White House, Mr Biden said. But he said he would happy for Vice-President Mike Pence to attend the inauguration.
The latest death is that of US Capitol Police officer Brian Sicknick, who succumbed to his injuries in hospital.
The FBI and Washington police will jointly investigate his death, although they have not yet said whether it will be treated as murder.
Wednesday's violence came hours after Mr Trump encouraged his supporters to fight against the election results as Congress was certifying Mr Biden's victory in the November vote.
Under pressure, Mr Trump released a recorded statement late on Thursday condemning the storming of the US Capitol as a "heinous attack".
How unusual is Trump's snub of the inauguration?
It is highly unusual but not unprecedented: the last president to skip the inauguration of his successor was Andrew Johnson, in 1869.
Mr Trump has now admitted defeat in the 3 November election and has promised a peaceful transfer of power. However, he has repeated baseless claims of widespread voter fraud.
Meanwhile, House Democrats plan to introduce articles of impeachment next Monday accusing the outgoing president of incitement of insurrection.
Nearly 160 House Democrats have signed on to the bill, which was drafted by congressmen Ted Lieu of California and David Cicilline of Rhode Island while they were sheltering in place during Wednesday's chaos at the Capitol.
If the House votes to pass an impeachment, proceedings would move to the Senate. But there is so far no sign that the two-thirds of votes required to convict the president can be found in the Republican-controlled upper chamber.
The White House responded in a statement: "A politically motivated impeachment against a President with 12 days remaining in his term will only serve to further divide our great country."
House Speaker Nancy Pelosi previously said her preference was for Mr Trump to be removed using the 25th Amendment, which allows the vice-president to step up if the president is unable to perform his duties owing to a mental or physical illness.
But there is no sign of the support from the vice-president and cabinet members needed to trigger this constitutional process.
Time is tight, with just 12 days remaining in Mr Trump's presidential term.
On Friday, Mrs Pelosi said she had spoken to the top US military official, the Chairman of the Joint Chiefs of Staff, to prevent Mr Trump from accessing US nuclear codes.
Separately, one of Mrs Pelosi's staff members revealed that a laptop had been stolen from her office during the mob invasion of Congress.
Trump's announcement that he will not attend Joe Biden's inauguration, breaking with a long American tradition, should not come as a huge surprise. He only recently, and reluctantly, acknowledged his presidential defeat, after months of unfounded allegations that a landslide electoral victory had been stolen from him.
The terse message, posted on Twitter, will undercut the president's call for "healing and reconciliation" made in the White House video he released last night. It suggests Trump, far from being at peace with his defeat, still harbours the kind of anger and resentment he has displayed in recent days.
He will not graciously welcome the Bidens to Washington as part of his promised "smooth, orderly and seamless transition of power". He may not even be anywhere near Washington when they arrive.
Instead, scripted Trump and Twitter Trump reveal two very different attitudes.
Already, Trump has tweeted about the "giant voice" his supporters will continue to have. The question is whether Trump is writing a coda to his presidency or just clearing his throat.