There have been discussions at the White House about Trump leaving Washington DC on January 19, a source familiar with the matter said.

He is expected to travel to his Florida resort, the source said.

"To all of those who have asked, I will not be going to the Inauguration on January 20th," Trump wrote on Twitter.

Earlier on Friday, Democrats were discussing whether to move forward with the quick impeachment of Trump if his cabinet doesn't try to remove him first, moving swiftly two days after the Capitol was ransacked by a pro-Trump mob.

House Democrats are set to hold a caucus meeting at noon, the first since Wednesday's harrowing events at the Capitol.

House Speaker Nancy Pelosi discussed the prospect of impeachment with her leadership team on Thursday night, hours after announcing that the House was willing to act if Vice President Mike Pence and other officials did not invoke Section 4 of the 25th Amendment - the forceful removal of Trump from power by his own cabinet.

Though Trump has less than two weeks in office, lawmakers and even some in his administration began discussing options for his removal on Wednesday afternoon.

Representative Katherine Clark, a member of House Democratic leadership, said procedural moves could allow them to move far quicker than they did on Trump's impeachment last year.

"I can confirm that we have had discussions about it and I would hope that the Speaker would move forward if the vice president refuses to do what he is required to do under the constitution," said Representative James Clyburn, the No. 3 House Democrat, on CNN.

"Everyone knows that this president is deranged."

Pelosi and Senate Democratic leader Chuck Schumer have called for Trump's cabinet to invoke the 25th Amendment to the constitution to force Trump from office before president-elect Joe Biden is inaugurated on January 20.

Schumer said he and Pelosi tried to call Pence early on Thursday to discuss that option but were unable to connect with him.

While the House could quickly vote to impeach Trump, it is extremely unlikely that Congress could remove the president in the next 13 days.

The Senate would have to receive the articles and then hold a trial and vote on them.

And even if it did so, the Republican Senate would be unlikely to vote to convict.

Democrats are set to narrowly take the Senate when Biden is inaugurated but Senate Majority Leader Mitch McConnell holds the gavel until then.

Biden distanced himself from his fellow Democrats' push to oust Trump with the 25th Amendment.

Andrew Bates, a spokesman for the president-elect, said Biden was focused on taking office on January 20 "and will leave it to Vice President Pence, the cabinet and the Congress to act as they see fit".

Pelosi said in a letter to Democratic lawmakers on Friday that she had spoken to the top US military commander on Friday, Army General Mark Milley, about taking precautions to ensure that Trump cannot initiate hostilities or order a nuclear strike in his remaining 12 days in office.

"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," Pelosi said in a letter to colleagues.

Australian Associated Press