National Guard troops have been sent en masse to Washington DC, to deter any repeat of last week's deadly riots.
The FBI has warned of possible armed marches by pro-Trump supporters at all 50 state capitols.
Meanwhile, the Biden team has set out plans to reverse key Trump policies.
In the hours after Mr Biden sets foot in the White House, he will embark on a blitz of executive actions designed to signal a clean break from his predecessor's administration, according to a memo seen by US media.
Among the actions: