WASHINGTON — A federal prosecutor alleged in court Tuesday that a man arrested in Minneapolis for his part in the Jan. 6 insurrection wanted a violent mass uprising against the U.S. government to happen.

The trial of 44-year-old Brian Christopher Mock is underway, marking the first case from someone arrested in Minnesota in connection with the Capitol attack to go to trial. The case is being heard by a D.C. federal judge in a building near the U.S. Capitol.

"The defendant believed he had to overthrow the government to save America," Assistant U.S. Attorney Michael Gordon said Tuesday morning. He described Mock as someone who "was prepared to die" on Jan. 6.

A crowd of then-President Donald Trump's supporters violently stormed the U.S. Capitol on the day that Congress was set to certify the results of the 2020 presidential election Trump had lost.

Mock has been indicted on 11 counts, with three of the charges accusing him of "assaulting, resisting, or impeding" officers, and also a count of "assaulting, resisting, or impeding certain officers using a dangerous weapon."

He is accused in court filings of shoving two officers to the ground, throwing a flagpole at law enforcement and shoving the back of an officer. Mock appeared in court Tuesday in a gray three-piece suit and fiddled at times with a pen.

In an opening statement for the federal government Tuesday morning, Gordon alleged Mock was upset by the results of the 2020 presidential election and believed the election was stolen.

Mock's defense attorney, Peter Moyers, did not make an opening statement Tuesday but is expected to later in the trial. The trial does not have a jury, and is instead being heard by a federal judge who will hand down a verdict.

Mock claimed in an earlier court filing that there was "dereliction of duty, insubordination and excessive use of force by the United States Capitol Police and other law enforcement agencies" on Jan. 6, 2021.

Much of Tuesday's trial action was focused on prosecution witnesses, including Stevin Karlsen who was a U.S. Capitol police officer. Karlsen, who has since left the police department after defending the Capitol from rioters on Jan. 6, was allegedly shoved to the ground by Mock.

Karlsen testified about a sense of panic and feeling defenseless down on the ground "with all these people swarming me," before an officer helped him get up.

Moyers questioned Karlsen about a report the then-officer made after the attack and a riot shield being by his feet at the time of the alleged assault. Karlsen later said in court that he fell because he was pushed.