Some members of Donald Trump's cabinet have been discussing invoking the 25th Amendment of the US Constitution to remove him from office immediately, according to reports.
Prominent Republicans have accused the president of inciting the violence which led to the Capitol building being stormed and four people dying.
A source familiar with the situation has said some cabinet members and Trump allies have spoken about invoking the 25th Amendment, despite there being just two weeks before Joe Biden is inaugurated, according to Reuters.
Several Democrats were also drafting a letter to Mr Pence demanding he invoke the 25th, NBC News reported.
What is the 25th Amendment?
Whenever a president is, for any reason, unable to carry out their duties, the 25th Amendment to the US Constitution can be invoked.
The amendment states that a president who knows they are or will be unable to perform the duties of office can notify Congress.
This is usually if a president is to undergo a surgical operation where they will be unconscious.
The vice president then becomes the acting president until the president sends another notice to declare he is once again able to do the job.
But, the fourth section of the amendment lays out what happens if the president becomes unable to discharge his duties but does not transfer power.
This section has never been invoked.
It states that the vice president and the majority of the cabinet would have to declare the president unfit to lead.
They would then send a letter to the House speaker and president pro tempore - the second-highest ranking official in the Senate - saying so. The vice president then becomes acting president.
If the president ultimately becomes ready to resume his duties, the president can send a letter saying this. But if the vice president and majority of the cabinet disagree, they can send a letter to Congress within four days. Congress would then have to vote.
The president resumes his duties unless both houses of Congress agree by a two-thirds majority to say he is not ready.
What happens if the president and vice president both become incapacitated?
First in line to serve as the acting president is the House speaker, now Nancy Pelosi, followed by the president pro tempore of the Senate, who is now Chuck Grassley of Iowa, followed by members of the cabinet.
But Ms Pelosi or Mr Grassley might be reluctant to accept the role, because they would be required to resign from Congress in order to take the position and could serve only until Congress finally decided who the president will be.
Has the amendment been considered for Mr Trump before?
Yes. The issue was raised when the president was treated in hospital for coronavirus in October, but he did not invoke the 25th.
Later that month, House Speaker Nancy Pelosi announced legislation that would create a commission to allow Congress to intervene under the amendment to remove the president from executive duties.
Why was the amendment introduced in the first place?
It was brought in following the assassination of President John F Kennedy in 1963.
His successor Lyndon Johnson promised in 1965 to propose laws ensuring there was a continuation of leadership should a president become disabled or die.
It addressed the Kennedy situation by saying that whenever a president dies or resigns, the vice president becomes president.
Congress passed the amendment later that year and it was ratified in 1967.
Has it been invoked before?
Yes. Presidents have temporarily relinquished power but not all invoked the 25th amendment.
Previous transfers of power have generally been brief and happened when the president was undergoing a medical procedure.
In 2002, President George W Bush became the first to use section three to temporarily transfer power to Vice President Dick Cheney while Mr Bush was given a general anaesthetic when he had a colonoscopy.
President Bush also temporarily transferred power again in 2007 to undergo another colonoscopy.
In 1985, President Reagan temporarily transferred power to Vice President George H W Bush while undergoing surgery to remove a polyp from his colon.
But he said at the time he was not formally invoking the 25th amendment.
Despite President Reagan being shot in 1981, the 25th was not invoked.
White House senior staff members discussed the measure, but Vice President Bush was travelling at the time. When he returned to Washington, the president's condition had stabilised, and doctors anticipated a full recovery.
Analysis: The 25th Amendment is a nuclear option - the bar is extremely high
By Cordelia Lynch, US correspondent
As Donald Trump was fuming about what he sees as betrayals in the White House on Wednesday night, members of his team weighed up whether to finally jump from his sinking ship.
Other senior administration officials, so alarmed by his conduct, reportedly discussed whether the cabinet might invoke the 25th Amendment.
Under the 25th Amendment, the president can be removed from office by the vice president plus a majority of the cabinet, or by the vice president and a body established by Congress, if they determine he "is unable to discharge the powers and duties of his office".
The process which allows for a rogue or incapacitated president to be forcibly removed is considered the last resort option.
But even those who have stood by Trump til the end are fearful that if he remains in office, even for a few days, he could take actions that could cause further violence and death.
The talks got under way in the wake of the carnage that unfolded in the capitol. But they were said to be informal with no indication of an immediate plan of action.
Democrats on the House Judiciary Committee sent a letter to Vice President Mike Pence yesterday evening imploring him to invoke the 25th Amendment.
And even the business world has been encouraging drastic action.
The head of a major US business group that represents 14,000 companies including Exxon Mobil Corp, Pfizer Inc and Toyota Motor Corp urged senior US officials to do the same.
The National Association of Manufacturers Chief Executive Jay Timmons said Trump "incited violence in an attempt to retain power, and any elected leader defending him is violating their oath to the Constitution and rejecting democracy in favor of anarchy. ... Vice President (Mike) Pence, who was evacuated from the Capitol, should seriously consider working with the Cabinet to invoke the 25th Amendment to preserve democracy".
But the bar to do it is extremely high.
Mike Pence would have to be on board, according to the text of the amendment. Pence would also need either a majority of Trump's cabinet officials to agree the president is unfit for office and temporarily seize power from him. Trump could dispute their move with a letter to Congress. Pence and the cabinet would then have four days to dispute him. Congress would then vote. And it requires a two-thirds supermajority, usually 67 senators and 290 House members to permanently remove him.
On top of all that, Donald Trump has now finally committed to a peaceful transfer. Of course many still fear what he might do in the next two weeks.
Supporters or enablers on Congress depending on how you see them, have started to part ways with Mr Trump. We may also see more resignations today. But, the 25th Amendment is a nuclear option and a protracted process. It's hard to imagine it happening now. But it's easy to see some deeply tense and potentially dangerous days ahead.