Two leaders of the far-right Oath Keepers militia, including founder Stewart Rhodes, were found guilty of sedition on Tuesday in the most high-profile case yet stemming from the January 6, 2021 attack on the US Capitol by supporters of then-president Donald Trump.

A federal jury convicted Rhodes, 57, and Kelly Meggs, 53, leader of the militia's Florida chapter, of the rarely pursued charge of seditious conspiracy, which carries up to 20 years in prison.

The 12-person jury acquitted three other members of the Oath Keepers -- Kenneth Harrelson, Jessica Watkins and Thomas Caldwell -- who faced the sedition charge, but it convicted them of lesser offenses such as obstructing an official proceeding.

Rhodes, an eyepatch-wearing former soldier and Yale law school graduate, and the four other group members were accused of plotting to keep Trump in power and overturn the results of the 2020 presidential election won by Democrat Joe Biden.

During the nearly two-week trial in Washington, prosecutors said the Oath Keepers "concocted a plan for an armed rebellion... plotting to oppose by force the government of the United States."

Hundreds of Trump supporters have been arrested for their roles in the assault on Congress but they have faced less serious charges than those lodged against Rhodes and the other Oath Keepers.

The jury deliberated for three days before reaching a verdict in the case, which the defendants characterized as a political trial carried out by the Biden administration against supporters of Trump, who has announced plans to run for the White House again in 2024.

US Attorney General Merrick Garland named a special counsel this month to oversee the investigation into Trump's own efforts to overturn the election result and the attack on Congress by his supporters.

The special counsel will also take over the Justice Department's probe into a cache of classified government documents seized in an FBI raid on Trump's Mar-a-Lago residence in Florida in August.

- 'Off-mission' -
A not-guilty verdict on the sedition counts for all five defendants would have been a setback for the Department of Justice, which plans to try members of the Proud Boys, another right-wing extremist group, on the same charges.

The verdict was hailed by the congressional committee investigating the Capitol assault.

"Today’s convictions are a victory for the rule of law and reinforce the fact that the violence of January 6th included a deliberate attempt to overturn the results of the 2020 election and block the transfer of presidential power," a statement from the committee's chairs, Democratic Congressman Bennie Thompson and Republican Liz Cheney, said.

Edward Tarpley, an attorney for Rhodes, said he was "disappointed."

"There was no evidence introduced indicating that there was a plan to attack the Capitol," Tarpley told reporters.

During the trial, prosecutors accused the Oath Keepers of stocking weapons at a hotel near Washington and joining the crowd that stormed the Capitol in a bid to block the certification by Congress of Biden's election victory.

Prosecutors showed videos of the attack by dozens of group members dressed in military-style combat gear.

Prosecutors also showed the jury text messages between Rhodes and his followers that called for action if Trump himself failed to act to prevent certification of Biden as the next president.

Rhodes did not personally enter the Capitol but directed his followers like a battlefield general, prosecutors said.

Rhodes took the witness stand during the trial and denied his group planned to assault the congressional complex, saying they were in Washington only to provide security at rallies.

"It was not part of our mission for that day to enter the Capitol for any reason," Rhodes said.

Speaking in military jargon, he admitted that a number of Oath Keepers went "off-mission" and entered the building.

He said Meggs, the Florida chapter head, was "an idiot" for taking his people inside.

"I think it was stupid to go into the Capitol. It opened the door for the political persecution of us. And that's where we are," Rhodes told the court.