United States President Donald Trump on Friday said he would not attend his successor Joe Biden's swearing-in on January 20, hours after he vowed to ensure a "smooth, orderly and seamless" transition of power.
"To all of those who have asked, I will not be going to the Inauguration on January 20th," Trump tweeted.
The last US president to skip the inauguration of his successor was Andrew Johnson, in 1869.
After weeks of falsely claiming that he had won the November 3 election, Trump, a Republican, had not been expected to attend the swearing-in of Biden, a Democrat.
Trump's tweet came on a day the congressional committee that organised the ceremony announced that the swearing-in will take place on the Capitol's West Front as planned, despite the pro-Trump mob that stormed the Capitol on Wednesday.
The rioters had over run the platform constructed for the event as well as the rest of the Capitol building.
In a statement, the Joint Congressional Committee on Inaugural Ceremonies said that Wednesday "was a sad and solemn day for our country. The outrageous attack on the Capitol, however, will not stop us from affirming to Americans — and the world — that our democracy endures.
"Our committee's bipartisan, bicameral membership remains committed to working with our many partners to execute ceremonies that are safe and showcase our determined democracy."
In the wake of the violence, security for the inaugural ceremony will be extremely tight, US media reports said.
There will be few guests, and the incoming Biden administration has already urged people not to come to Washington for the event, also because of the coronavirus pandemic.
Faced with mounting defections from senior aides and longtime supporters over Wednesday's assault on the Capitol, Trump issued a video late on Thursday in which he acknowledged publicly for the first time that power will be transferred to Biden.
"A new administration will be inaugurated on January 20th," he continued. "My focus now turns to ensuring a smooth, orderly and seamless transition of power. This moment calls for healing and national reconciliation."
"To the citizens of our country, serving as your president has been the honor of my lifetime. And to all of my wonderful supporters, I know you are disappointed, but I want you to know that our incredible journey is only just beginning," he added.
Top congressional Democrats have urged US Vice-President Mike Pence to begin a process of declaring Trump unfit for office.
House Speaker Nancy Pelosi and Senate Democratic leader Chuck Schumer said Trump should be removed for "his incitement of insurrection".
"The President's dangerous and seditious acts necessitate his immediate removal from office," they said in a joint statement.
The two leaders called for Trump to be ousted 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.
