A Donald Trump supporter was sentenced to five years in prison for assaulting police officers during the attack on the US Capitol, the harshest punishment yet handed down in the investigation into the Jan 6 violence.

Robert Scott Palmer, 54, was seen in videos and photos wearing an American flag jacket decorated with pro-Trump patches and a hat reading “Florida for Trump” as he threw boards, a fire extinguisher and other objects at police outside the Capitol.

He had tried to enter the Capitol but was ultimately pushed back by pepper spray deployed by security officials.

After that he continued to throw things at officers, until he was hit by a rubber bullet.

Federal judge Tanya Chutkan rejected Palmer’s arguments for leniency of a troubled childhood and a handwritten apology that said that he and others had been duped into attacking the Congress by the former president, whom he called “tyrannical” and “desperate to hold on to power”.

“I realise that we meaning Trump supporters had been lied to,” he wrote.

Prosecutors pointed out that even after his Oct 4 guilty plea, Palmer continued to defend his actions, labelling police the aggressors on a fundraising website page he set up.

“Palmer purposefully joined a large group of rioters with the specific intent of interfering with the nation's electoral process,” the prosecutors told the court in a sentencing memo.

“Palmer’s violence was in pursuit of his political goal of subverting a democratic election and the peaceful transition of power.”

The previous stiffest sentence in the Capitol attack was 41 months, given to two men who were charged with obstructing an official proceeding but were not accused of assaulting law enforcement.

More than 700 people have been charged in the attack, most of them for minor offences such as illegally entering the Capitol.

But several dozen face assault and deadly weapons charges as well as conspiracy, which could lead to heavy sentences. (AFP)

•Robert Palmer had tried to enter the Capitol but was ultimately pushed back by pepper spray deployed by security officials. PHOTO: NYTIMES

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