The leader of the Proud Boys extremist group has been jailed for more than five months for burning a Black Lives Matter banner that was torn down from a Washington, DC, church and bringing two high-capacity firearm magazines into the US capital days shortly before the January 6 riot.

Enrique Tarrio told a Washington court via videoconference he was “profusely” sorry for his actions, calling them a “grave mistake”.

Tarrio, from Miami, was arrested as he arrived in Washington two days before thousands of supporters of then-president Donald Trump – including members of the Proud Boys – descended on the Capitol and disrupted the certification of the electoral college vote.

Tarrio was ordered to stay away from Washington.

Authorities say Proud Boys members stole the banner that read #BLACKLIVESMATTER from the Asbury United Methodist Church on December 12 and then set it alight.

Tarrio admitted the act on social media and in comments to media outlets.

He was arrested on January 4. At the time of the arrest police found two high-capacity firearm magazines.

Tarrio pleaded guilty last month to destroying property and possessing a “large-capacity ammunition feeding device”.

On Monday (local time), Judge Harold Cushenberry said Tarrio deserved even more time behind bars than the three months prosecutors had sought, sentencing him to 155 days jail.

Proud Boys members describe themselves as a men’s club for “Western chauvinists”. Its members frequently have engaged in street fights with anti-fascist activists at rallies and protests.

Nearly 600 people have been charged in the investigation into the Capitol riot.