The FBI has warned of possible armed protests being held across the US as Trump supporters and far-right groups call for demonstrations before Joe Biden is sworn in as president.
There are reports of armed groups planning to gather at all 50 state capitols and in Washington DC in the run-up to his 20 January inauguration.
Security will be tight for the event after a pro-Trump mob stormed Congress.
House Democrats say a vote to impeach the president will happen on Wednesday.
They accuse President Trump of “incitement of insurrection” and say the vote will be held unless Vice-President Mike Pence invokes constitutional powers to remove Mr Trump from office. There is no sign Mr Pence is prepared to do so.
Mr Biden and Vice-President-elect Kamala Harris are expected to be sworn in at a ceremony at the Capitol. The Biden team had already urged Americans to avoid travelling to the capital because of the Covid-19 pandemic, a call that is now being repeated by local authorities.
Security officials have said there will be no repeat of the breach seen on 6 January, when thousands of pro-Trump supporters were able to break into the building where members of Congress were voting to certify the election result.
Five people died in the riot, which happened after Mr Trump repeated unsubstantiated claims of fraud in the November vote and encouraged his supporters to march on the Capitol.
Since then, calls for Mr Trump’s resignation, removal from office or impeachment have grown among Democrats and some Republicans. Mr Trump has made no public statements since he was banned from several social media platforms – including Twitter – on Friday.
He became the third US president to be impeached in December 2019 over charges of breaking the law by asking Ukraine to investigate his rival in the presidential election. The Senate cleared him.