State officials across the United States are preparing for potentially violent demonstrations in support of President Donald Trump in the days leading up to the January 20 inauguration of President-elect Joe Biden.

Several states, including California, Michigan, Pennsylvania, Kentucky and Florida, had activated their National Guard forces to bolster security as of Saturday.

Meanwhile, a man with a loaded handgun and more than 500 rounds of ammunition has been arrested at a security checkpoint near the US Capitol.

Wesley Allen Beeler, of Virginia, had driven to a checkpoint on Friday evening and tried to use a fake credential to access the restricted area where Biden will be inaugurated next week, according to a document filed in Washington, DC Superior Court.

As officers checked against an authorised access list, one of them noticed decals on the back of Beeler’s pick-up truck that said “Assault Life”, with an image of a rifle, and another with the message: “If they come for your guns, give ’em your bullets first.”

‘An honest mistake’

Under questioning, Beeler told officers he had a Glock handgun in the vehicle.

A search uncovered a loaded handgun, more than 500 rounds of ammunition, shotgun shells and a magazine for the gun, the court document said.

Beeler was arrested on charges including possession of an unregistered firearm and unlawful possession of ammunition, a police report said.

Following his arrest, Beeler said it was “an honest mistake” and that he was a private security guard who got lost on his way to work near the Capitol.

The security build-ups come after the FBI warned police agencies across the US of possible armed protests outside all 50 state capitol buildings starting on Saturday and lasting through Biden’s inauguration on Wednesday.

Experts said the capitals of battleground states Wisconsin, Michigan, Pennsylvania and Arizona are among the most at risk of violence.

Those states have been central to Trump’s baseless claims of widespread election fraud, which he has used to foment unrest among his supporters, who stormed the US Capitol building as Congress met to certify Biden’s victory.

Rallies expected in all states

On Sunday, the anti-government “Boogaloo” movement plans to hold rallies in all 50 states.

Texas state officials closed the Capitol through Inauguration Day, with Department of Public Safety Director Steve McCraw saying late on Friday that intelligence indicated “violent extremists” may seek to exploit planned armed protests in Austin to “conduct criminal acts”.

In Michigan, a fence was erected around the Capitol in Lansing and troopers were mobilised from across the state to bolster security. The legislature cancelled meetings next week, citing concerns about credible threats.

“We are prepared for the worst but we remain hopeful that those who choose to demonstrate at our Capitol do so peacefully,” Michigan State Police Director Joe Gasper said during a news conference on Friday.