All 50 US claims and the District of Columbia (DC) are in alert for feasible violent protests this weekend, ahead of President-elect Joe Biden's inauguration in Wednesday.
National Guard troops have been sent en masse to Washington DC, to deter any kind of 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 offers lay out plans to reverse key Trump policies.
In the hours after Mr Biden sets foot in the White House, he'll go on a blitz of executive actions made to signal a clean break from his predecessor's administration, according to a memo seen by US media.
Among the actions:
He'll return the US to the Paris climate agreement - a global pact on cutting carbon emissions
He will repeal the controversial travel ban on a list of mostly Muslim-majority countries
He will try to make wearing masks mandatory on federal property and when travelling interstate
Although Mr Biden, like President Trump, can use executive orders as a way of bypassing Congress on some people issues, his $1.9tn (£1.4tn) stimulus strategy announced earlier this week will need to be approved by lawmakers, as will a bill on immigration reform.
A lot of Washington DC will be locked straight down before Wednesday's inauguration, with National Guard troops deploying within their thousands.
Various streets - some miles from the Capitol, the website of deadly rioting in 6 January - have been blocked away with concrete barriers and metal fences.
The National Mall, which is generally thronged with thousands of folks for inaugurations, has been shut at the request of the trick Service - the agency charged with protecting the president.
The Biden team had already asked Americans in order to avoid travelling to the country's capital for the inauguration as a result of the Covid-19 pandemic. Local officials said persons should watch the function remotely.
Sunday is likely to also be a special focus for protests, after posts on pro-Trump and far-right internet needed armed demonstrations on that day.
Some militias have told their followers not to attend, however, citing heavy security or claiming the planned events are police traps.
Capitol Police confirmed on Saturday an armed Virginia man carrying a "non-government issued credential" have been stopped and arrested at a good security checkpoint on Friday with in least 1 gun and 509 rounds of ammunition.
But the guy, named Wesley Allen Beeler, was later introduced from custody and told the Washington Content that he didn't intend to carry a firearm into Washington, where he said he had been working with a private security firm.
"I pulled up to a checkpoint after getting shed in DC because I'm a good country boy," he said. "I confirmed them the inauguration badge that was given to me."
The tough security measures follow weekly where Donald Trump became the first US president to be impeached twice. He nowadays faces a Senate trial, on a charge of "incitement of insurrection" from the storming of the US Capitol by sets of his supporters. They have therefore in a bid to thwart Congress certifying Joe Biden's victory in the presidential election.
Dozens of arrests have already been made in relation to the assault on the Capitol building.
Among the most recent is a far-right media personality referred to as Baked Alaska - genuine name Anthime Joseph Gionet. A criminal complaint says he was arrested in Houston, Texas on Friday and charged with two federal crimes, including violent entry and disorderly conduct on Capitol grounds.