The US House of Representatives could vote as early as Tuesday on an article of impeachment against President Donald Trump, a senior Democrat has said.
House Democrats plan to introduce a charge of “incitement of insurrection” against the president over his role in the violent storming of the Capitol.
House whip James Clyburn told CNN action would be taken this week.
But the party may not send any articles to the Senate for trial until after Joe Biden’s first 100 days in office.
“Let’s give President-elect Biden the 100 days he needs to get his agenda off and running,” Mr Clyburn said.
That would allow Mr Biden to confirm his new cabinet and kick-start key policies including tackling coronavirus – something that would have to wait if the Senate had already received the impeachment articles.
Democrats and an increasing number of Republicans accuse Mr Trump of encouraging last Wednesday’s riot in Congress in which five people died.
But no Republican senators have said they will vote to convict him of wrongdoing in the Senate.
A second Republican senator, Pat Toomey, called for Mr Trump to resign on Sunday.
“I think the best way for our country…. is for the president to resign and go away as soon as possible,” Sen Toomey told NBC’s Meet the Press.
“I acknowledge that may not be likely, but I think that would be best.”
Lisa Murkowski, from Alaska, was the first Republican senator to urge the president to go. Ben Sasse, a Republican senator from Nebraska, has said he would consider articles of impeachment if approved by the House.
Meanwhile, former Republican California governor Arnold Schwarzenegger labelled Mr Trump as the “worst president ever” in a social media video on Sunday.
The actor likened Wednesday’s violence to that of the Kristallnacht, or the Night of Broken Glass, during which Jewish property was destroyed in Nazi Germany in 1938.
As investigators try to prosecute rioters who stormed the Capitol, police departments in Virginia and Washington state have placed officers on administrative leave for allegedly attending the events while off-duty.
Fire departments in Florida and New York City have also said some of their members may have been present when the mob broke into the Capitol, according to Reuters news agency.
The White House has dismissed the impeachment as a “politically motivated” move that would “only serve to further divide our great country”.
If the process does go ahead, Mr Trump could become the only president in US history to have been impeached twice.
For that to happen, impeachment charges must be brought to the House and passed in a vote.
“It may be Tuesday or Wednesday before action is taken,” House whip Mr Clyburn told CNN, “but I think it will be taken this week.”
Proceedings would then move to the Senate, where a two-thirds vote is necessary for a president’s removal. If he is convicted, the Senate could also hold a vote to bar Mr Trump from holding public office again.
However, Mr Clyburn, a congressman from South Carolina, said he did not think it would possible to impeach and hold a trial before Mr Trump leaves office in 10 days’ time.
Instead Democrats are considering delaying sending impeachment articles to the Senate.
They have already called on Vice-President Mike Pence to invoke the 25th Amendment, which would allow him to become acting president.
Such a course of action is said to be highly unlikely, and there is no sign that Vice-President Pence is prepared to use the amendment.
However, Mr Pence did appear to distance himself further from Mr Trump on Sunday, by saying he planned to attend Joe Biden’s inauguration on 20 January.
Mr Trump has said he will not attend the swearing-in ceremony. He has now admitted defeat in the 3 November election and has promised a peaceful transfer of power, but has continued to peddle baseless claims of widespread voter fraud.
President-elect Joe Biden said impeachment was for Congress to decide, but said he had thought “for a long time President Trump was not fit to hold the job”.