Prosecutors said the 2021 attack on Congress by Trump supporters was "an unprecedented assault on the seat of American democracy" that was "fuelled by lies" from the former president.

The indictment alleged Trump and his Republican allies repeatedly lied about the results in the two months after he lost the November 2020 election to Democrat Joe Biden.

It is also alleged Trump pressured his vice president, Mike Pence, and state election officials to take action to help him cling to power.

'Emotionless' Trump appears in court - follow latest updates

The four counts against Trump include conspiracy to defraud the US, to deprive citizens of their right to have their votes counted, and to obstruct an official proceeding - interrupting Congress during its certification of Mr Biden.

The most serious charges, obstruction of an official proceeding and conspiracy to obstruct, both carry a maximum prison sentence of 20 years. The charge of conspiracy to defraud the United States has a maximum term of five years, while conspiracy against rights has a maximum of 10 years.

In court in Washington DC, Trump did not appear to show much emotion and was not angry or upset, according to witnesses who were there.

He wore a suit and red tie and chatted with his lawyers before the judge arrived. At one point he scribbled notes on a piece of paper in front of him and handed it to his lawyer.

Before entering his plea Trump answered basic questions from the judge and was informed of the charges against him and the potential penalties.

US Magistrate Judge Moxila Upadhyaya set the next hearing for 28 August, just days after the first debate in the 2024 Republican presidential primary. But she said Trump would not be required to attend.

The arraignment, which lasted around half an hour, took place just half a mile from the US Capitol, the building Trump's supporters stormed on January 6 2021.

Despite his legal woes Trump is still the frontrunner for the Republican nominee to become president.

Speaking after his court appearance and before bearing his plane back to New Jersey, he said: "This is a very sad day for America.

"When you look at what is happening this is a persecution of a political opponent. This was never supposed to happen in America.

"This is a persecution of a person that is leading by very very substantial numbers in the Republican primary and leading Biden a lot. So if you can't beat him you persecute him or you prosecute him, we can't let this happen in America."

Speaking outside the court earlier, Trump's legal spokesperson Alina Habba said: "This is election interference at its finest, against the leading candidate for president, from either party.

"President Trump is under siege in a way that we have never seen before. Donald Trump and his legal team, and everyone on his team, will continue to fight - not for him, but for the American people."

She claimed Trump had told his supporters who disagreed with the election result to "go patriotically and peacefully and protest".

Read more:
The case against Donald Trump
Trump's defence strategy and how his legal team could challenge the charges
What are the investigations the former US president is facing?

Third criminal case brought against Trump in six weeks

It is the third criminal case brought against Trump in the last six weeks.

He was charged in New York with falsifying business records in connection with an alleged hush money payment to porn actor Stormy Daniels during the 2016 presidential campaign.

He has also been charged with 40 felony counts in Florida, accused of illegally retaining classified documents at his Mar-a-Lago estate and refusing government demands to return them.

He has pleaded not guilty in both cases, which are set for trial next year.