Updated 9.40pm

Former president Donald Trump arrived in federal court in the US capital on Thursday to answer historic charges of leading a criminal conspiracy that sought to defraud the American people by overturning the 2020 election.

Trump, the frontrunner for the 2024 Republican presidential nomination, is being arraigned at the same downtown Washington courthouse where hundreds of his supporters who took part in the January 6, 2021 attack on the US Capitol have been convicted and sentenced.

Shortly before leaving his Bedminster, New Jersey, golf club for the flight to Washington, Trump defiantly doubled down on his baseless claim that the election was "stolen."

Trump is expected to enter a plea of not guilty at a hearing before magistrate judge Moxila Upadhyaya. He is likely to be fingerprinted but not have a mugshot taken.

The 77-year-old billionaire has already been charged in two other criminal cases, and the new conspiracy charges raise the prospect of his being further embroiled in legal proceedings at the height of next year's election campaign.

Metal barricades formed a security ring around the E. Barrett Prettyman courthouse where Trump's arraignment is taking place within sight of the Capitol that was stormed by his supporters on January 6.

Police and sniffer dogs gathered outside the court, where small groups of demonstrators holding placards milled about along with some curious tourists.

"Jail Trump Forever," read one sign held by a protestor. "Trump 24," read another held by a supporter.

"We wanted to see it," said Dave Werner, 52, of Houston, Texas, who was visiting the capital with his son Liam, 12. "It's a little bit being part of history."

The accusations that Trump and six unnamed co-conspirators plotted to upend the 2020 election result are the most serious of the cases threatening to derail his White House comeback bid.

"I am now going to Washington, D.C. to be arrested for having challenged a corrupt, rigged and stolen election," he posted on his Truth Social site, repeating what special counsel Jack Smith has called the "lies" about the 2020 vote that is at the heart of the indictment against him.

"It is a great honour, because I am being arrested for you," Trump told his social media followers.

A person dressed in a costume depicting former U.S. President Donald Trump as a baby walks in front of the E. Barrett Prettyman United States Courthouse on August 03, 2023 in Washington, DC. Photo: AFP

'Fueled by lies'

Earlier, Trump, in a post on Truth Social, accused President Joe Biden of seeking to charge him with "as many crimes as can be concocted."

"But soon, in 2024, it will be our turn," he wrote.

Biden, for his part, was asked during a morning bike ride while vacationing in Delaware if he would be following the arraignment. His response was a curt "No."

Smith, a former war crimes prosecutor at the Hague, unveiled a 45-page indictment of Trump on Tuesday charging him with conspiracy to defraud the United States and attempting to disenfranchise American voters with his false claims that he won the November 2020 election.

"The purpose of the conspiracy was to overturn the legitimate results of the 2020 presidential election by using knowingly false claims of election fraud," the indictment said.

Smith linked Trump's actions following his loss to Biden directly to the attack on the Capitol, which he called an "unprecedented assault on the seat of American democracy."

"It was fueled by lies," Smith said.

Multiple cases

Trump is scheduled to go on trial in Florida in May of next year on charges that he took top secret government documents to his Mar-A-Lago estate in Florida and refused to return them.

The twice-impeached former president also faces criminal charges in New York for allegedly paying election-eve hush money to a porn star.

He has pleaded not guilty in both those cases.

The election plot allegedly included attempts to pressure Mike Pence into throwing out Electoral College votes at the January 6 joint session of Congress called to certify Biden's win, which the vice president eventually refused to do.

Although Trump's arraignment will be before a magistrate judge, the actual case is to be heard by US District Court Judge Tanya Chutkan, an appointee of former Democratic president Barack Obama.

Chutkan, 61, ruled against Trump in 2021 when he filed a suit asserting executive privilege to block documents from being handed over to a congressional committee investigating the attack on the Capitol.

"Presidents are not kings," Chutkan said in her ruling.

Chutkan has also heard nearly three dozen cases involving participants in the Capitol riot and has handed out stiff sentences.

As president, Trump was impeached by the House of Representatives for seeking political dirt on Biden from Ukraine and over the events of January 6 but was acquitted by the Senate both times.