President Donald Trump said Friday local time he will skip President-elect Joe Biden's inauguration on January 20, undercutting his message a day earlier that he would work to ensure a "smooth, orderly and seamless transition of power."

Trump, who offered no clues for how he would spend his final hours in office, will be the first incumbent president since Andrew Johnson not to attend his successor's swearing-in. Traditionally, the incoming and outgoing presidents ride to the U.S. Capitol together for the ceremony, as a symbol of the nation's peaceful transition. Former President Barack Obama and his wife, Michelle Obama, and George W. and Laura Bush have said they will attend.

The decision to skip the symbolic transfer of power came two days after a violent mob of Trump's supporters occupied the Capitol for several hours as lawmakers were tallying the electoral votes that certified Biden's victory. Biden will become president at noon on Jan. 20 regardless of Trump's plans.

"To all of those who have asked, I will not be going to the Inauguration on January 20th," Trump tweeted. The move had been widely expected, as Trump for months falsely claimed victory in the election and promulgated baseless claims of voter fraud. His own administration said the election had been fairly run.

Sen. Rick Scott, a Florida Republican, urged Trump to reconsider.

"He is, of course, not constitutionally required to attend and I can imagine losing an election is very hard, but I believe he should attend. I plan to attend and believe it is an important tradition that demonstrates the peaceful transfer of power to our people and to the world," he said in a statement.

Vice President Mike Pence, who defied Trump on Wednesday when he refused to intervene in the certification process, was expected to attend the inauguration, according to one person close to him and one familiar with the inauguration planning. But Pence spokesman Devin O'Malley said in a statement Friday that he and the second lady "have yet to make a decision regarding their attendance."

Biden said Trump's decision to skip his inauguration is "one of the few things he and I have ever agreed on."

"It's a good thing, him not showing up," Biden told reporters Friday in Wilmington, Delaware, at a news conference after he introduced Cabinet nominees.

"He exceeded even my worst notions about him. He's been an embarrassment to the country, embarrassed us around the world. He's not worthy to hold that office," Biden said.

However, Biden said he is glad Vice President Mike Pence will attend his inauguration.

"He's welcome. I think it's important that as much as we can stick to what have been the historical precedents of how an administration changes should be maintained. And so Mike, the vice president, is welcome to come. We'd be honored to have him there, and to move forward in the transition," Biden said.

But Jen Psaki, the incoming White House press secretary, said last month that whether Trump attended the inauguration was not top of mind for Biden.

On Thursday, with 12 days left in his term, Trump finally bent to reality amid growing talk of trying to force him out early and acknowledged he'll leave peacefully.

Trump led off a video from the White House by condemning the violence carried out in his name a day earlier at the Capitol. Then, for the first time on camera, he admitted his presidency would soon end — though he declined to mention Biden by name or explicitly state he had lost.

"A new administration will be inaugurated on Jan. 20," Trump said in the video. "My focus now turns to ensuring a smooth, orderly and seamless transition of power. This moment calls for healing and reconciliation."

By next morning, however, Trump was back to his usual division. Instead of offering condolences to the police officer who died from injuries sustained during the riot, Trump commended the "great American Patriots" who'd voted for him.

"They will not be disrespected or treated unfairly in any way, shape or form!!!" he tweeted.

Thursday evening's address, which appeared designed to stave off talk of a forced early eviction, came at the end of a day when the cornered president stayed out of sight in the White House. Silenced on some of his favorite internet lines of communication, he watched the resignations of several top aides, including two Cabinet secretaries.

And as officials sifted through the aftermath of the pro-Trump mob's siege of the Capitol, there was growing discussion of impeaching him a second time as talk of invoking the 25th Amendment to oust him from the Oval Office continued.

The invasion of the Capitol building, a powerful symbol of the nation's democracy, rattled Republicans and Democrats alike. They struggled with how best to contain the impulses of a president deemed too dangerous to control his own social media accounts but who remains commander in chief of the world's greatest military.

"I'm not worried about the next election, I'm worried about getting through the next 14 days," said Republican Sen. Lindsey Graham of South Carolina, one of Trump's staunchest allies. He condemned the president's role in Wednesday's riots and said, "If something else happens, all options would be on the table."

Democratic House Speaker Nancy Pelosi declared that "the president of the United States incited an armed insurrection against America." She called him "a very dangerous person who should not continue in office. This is urgent, an emergency of the highest magnitude."

She said Friday in a statement to colleagues that she had spoken to the chairman of the Joint Chiefs of Staff about preventing Trump from initiating military actions or a nuclear strike.

"The situation of this unhinged President could not be more dangerous, and we must do everything that we can to protect the American people from his unbalanced assault on our country and our democracy," she wrote.

Pelosi was also meeting with the House Democratic caucus Friday to consider impeachment proceedings against the president for a second time. She and Democratic Senate leader Chuck Schumer have also called on Pence and the Cabinet to invoke the 25th Amendment to to force Trump from office — though the urgency of that discussion among Cabinet members and staff had diminished Thursday.

The talks reflected fears of what a desperate president could do in his final days, including speculation Trump could incite more violence, make rash appointments, issue ill-conceived pardons — including for himself and his family — or even trigger a destabilizing international incident.

Pence has not said publicly whether he would support invoking the 25th Amendment, but Democratic Sen. Joe Manchin said he did not think that was likely. "I'm just hearing he is basically not moving in that direction," he said, citing "my Senate channels."

The president's video Thursday was a complete reversal from the one he put out just 24 hours earlier in which he said to the violent mob: "We love you. You're very special." His refusal to condemn the violence sparked a firestorm of criticism and, in the new video, he at last denounced the demonstrators' "lawlessness and mayhem."

Aides said the video was also meant to slow the mass exodus of staffers and ward off potential legal trouble for Trump once he leaves office; White House counsel Pat Cipollone has repeatedly warned the president that he could be deemed responsible for inciting Wednesday's violence.

As for his feelings on leaving office, Trump told the nation that "serving as your president has been the honor of my lifetime" while hinting at a return to the public arena. He told supporters "our incredible journey is only just beginning."

Some of his loyalists headed for the exits, moving up their departures to protest the president's handling of the riot.

Transportation Secretary Elaine Chao became the first Cabinet member to resign. Chao, married to Senate Majority Leader Mitch McConnell, one of the lawmakers trapped at the Capitol on Wednesday, said in a message to staff that the attack "has deeply troubled me in a way that I simply cannot set aside."

Education Secretary Betsy DeVos followed. In her resignation letter Thursday, DeVos blamed Trump for inflaming tensions in the violent assault on the seat of the nation's democracy. "There is no mistaking the impact your rhetoric had on the situation, and it is the inflection point for me," she wrote.

Others who resigned: Matthew Pottinger, deputy national security adviser; Ryan Tully, senior director for European and Russian affairs at the National Security Council; and first lady Melania Trump's chief of staff Stephanie Grisham, a former White House press secretary.

Mick Mulvaney, Trump's former chief of staff-turned-special envoy to Northern Ireland, told CNBC that he had called Secretary of State Mike Pompeo "to let him know I was resigning. ... I can't do it. I can't stay."

"Those who choose to stay, and I have talked with some of them, are choosing to stay because they're worried the president might put someone worse in," Mulvaney said.

Mulvaney's predecessor in the chief of staff job, retired U.S. Marine Corps Gen. John Kelly, told CNN that the Cabinet should discuss invoking the 25th Amendment to remove Trump from office.

Staff-level discussions on the matter took place across multiple departments and even in parts of the White House, according to two people briefed on the talks. But no member of the Cabinet has publicly expressed support for the move.

In the West Wing, shell-shocked aides were packing up, acting on a delayed directive to begin offboarding their posts ahead of the Biden team's arrival.

The president has asked aides to explore a possible valedictory trip next week to the southern border as a means to highlight his immigration policies.