Pro-Trump protesters inside the US Capitol building
Pro-Trump protesters inside the US Capitol building Reuters/Michael Nigro/Sipa USA

The founder of the far-right group Oath Keepers and 10 others were indicted on Thursday for seditious conspiracy in the January 6, 2021 assault on the US Capitol, the Justice Department announced, according to AFP.

It was the first use of the potent sedition charge in the investigation of the Capitol attack.

Stewart Rhodes, 56, who founded and led the group, and another associate of the organization, Ed Vallejo, were arrested early Thursday.

Nine men with ties to the Oath Keepers who had been previously arrested on lesser charges in the violent attack, which temporarily shut down the US Congress, were also named as part of the alleged seditious conspiracy.

"Following the Nov. 3, 2020, presidential election, Rhodes conspired with his co-defendants and others to oppose by force the execution of the laws governing the transfer of presidential power by Jan. 20, 2021," the Justice Department said in a statement quoted by AFP.

It said that, in an effort to prevent Congressional certification of Joe Biden's victory over Donald Trump in the presidential election, they made plans for "breaching and attempting to take control of the Capitol grounds and building," it said.

While they did that, it said, some Oath Keeper members remained stationed just outside of Washington with weapons and ammunition, ready to bring them to the capitol as reinforcements if fighting escalated.

They were the first of the more than 725 charged in the Justice probe to be accused of sedition, a very rarely used charge that alters the perception of the attack.

Oath Keepers was named in a lawsuit filed last year by the NAACP and Rep. Bennie Thompson (D-MS) over the Capitol riots.

The lawsuit alleges that Trump incited the Capitol riot in violation of a Reconstruction Era law commonly referred to as the Ku Klux Klan Act. The civil complaint also names former New York City mayor Rudy Giuliani, as well as the Proud Boys.

Those charged Thursday face up to 20 years in prison on the conspiracy to sedition charge alone. Most also face other charges such as assault on law enforcement and disrupting Congress.

Meanwhile, the House committee probing the Capitol riots is continuing its own investigation. On Wednesday, the committee asked for information from Minority Leader Kevin McCarthy (R-CA).

The House committee has subpoenaed a slew of close associates of Trump. The House has already voted to hold two of them - former White House senior advisor Steve Bannon and former White House chief of staff Mark Meadows - in contempt of Congress for noncompliance with the subpoena.