An associate of the far-right Three Percenters militia group has been sentenced to more than seven years in prison for his role in storming the US Capitol on 6 January 2021.

It is the longest sentence imposed so far among hundreds of cases related to the insurrection by extremist supporters of Donald Trump who sought to stop the official congressional certification of Joe Biden’s election victory over his Republican rival.

Prosecutors said Guy Reffitt had told fellow members of the Texas Three Percenters militia group that he planned to drag the House speaker, Nancy Pelosi out of the Capitol building by her ankles “with her head hitting every step on the way down”, according to a court filing.

Reffitt was sentenced in Washington DC on Monday after being convicted by a jury in March of obstructing Congress’ joint session, of interfering with police officers outside the Capitol and of threatening his two teenage children if they reported him to law enforcement.

Justice department prosecutors recommended a 15-year prison sentence for Reffitt, with the duration warranted “for terrorism”.

The longest sentence before Reffitt’s 7.25-year term was handed down was five years and three months, for two men who admitted assaulting police officers at the Capitol.

Reffitt’s defense had asked for no more than two years in prison.

Videos captured the confrontation between outnumbered US Capitol police officers and a mob of people, including Reffitt, who approached them on the west side of the building that afternoon, shortly after Trump had held a rally calling on the crowd to go to the Capitol and urging supporters to “fight like hell” to keep him in power.

Reffitt was armed with a Smith & Wesson pistol in a holster on his waist, carried zip-tie handcuffs and was wearing body armor and a helmet equipped with a video camera when he advanced on officers, according to prosecutors.

He retreated after an officer pepper-sprayed him in the face, but he waved on other rioters who ultimately breached the building, prosecutors said.

Reffitt’s 19-year-old son, Jackson, testified that his father had told him and his sister, then 16, that they would be traitors if they reported him to authorities and warned them that “traitors get shot”.

The Three Percenters movement refers to the myth that only 3% of Americans fought in the revolutionary war against the British.

Reffitt lived with his wife and children in Wylie, Texas, a Dallas suburb. He drove to Washington with Rocky Hardie, a fellow member of the militia group.

Hardie testified that both of them attended Trump’s rally.

More than 840 people have been charged with federal crimes related to the riot. More than 340 of them have pleaded guilty and more than 220 have been sentenced, with nearly half of them receiving terms of imprisonment. Approximately 150 others have trial dates stretching into 2023.

Reffitt is one of seven Capitol riot defendants to get a jury trial so far. Jurors have convicted all seven on all counts.

The Department of Justice has not ruled out Trump and members of his cohort from its widening criminal investigation into events surrounding January 6 as well as the insurrection itself.

The attorney general, Merrick Garland, last week pledged “to bring to justice everybody who is criminally responsible for interfering with the peaceful transfer of power” and to pursue wrongdoing “without fear or favor”.

Separately, a bipartisan House select committee is investigating events leading up to, on and immediately after January 6 and has held a series of public hearings that are expected to resume in the fall, that also examine Trump’s role.