Thomas Cullen, the U.S. attorney for the Western District of Virginia, discusses the indictment of James A. Fields Jr. in Charlottesville last month. (Steve Helber/AP)

A self-professed neo-Nazi who allegedly used his car as a lethal weapon at a violent white-supremacists rally last August pleaded not guilty Thursday to more than two dozen federal hate crimes, one of which carries a possible death sentence.

James A. Fields Jr., 21, also is charged in state court with first-degree murder and other offenses stemming from the deadly mayhem Aug. 12 at the “Unite the Right” rally, which riveted national attention on the emergence of emboldened white supremacists.

After hours of chaotic clashes that day involving racist demonstrators and their opponents, counterprotester Heather D. Heyer, 32, was killed when a 2010 Dodge Challenger, which prosecutors say was driven by Fields, was intentionally rammed into another vehicle on a crowded street, sending bodies flying. Authorities said 35 other people were injured.

Clad in gray-and-white-striped jail clothes, Fields was ushered into U.S. District Court here in shackles Thursday, and he pleaded not guilty to 28 federal charges at his arraignment before Magistrate Judge Joel C. Hoppe.

Fields, who traveled to the rally from his Ohio home, told the judge that he is being treated for bipolar disorder, anxiety, depression and attention-deficit/hyperactivity disorder. He said he has been taking antipsychotic medication and anti-depressants.

He was arrested minutes after the Aug. 12 incident and has been jailed here for almost a year, awaiting state prosecution. On June 27, the Justice Department announced a parallel prosecution after obtaining an indictment of Fields on 28 counts of federal hate crimes.

James A. Fields Jr. is seen in a mugshot released by Charlottesville’s police department. (Handout ./Reuters)

Two of the counts are connected to Heyer’s death, and one is a possible capital offense, although federal authorities have not begun the process of deciding whether to seek the death penalty. The other hate-crime charges, each punishable by up to life in prison, are connected to many of the victims who were injured.

Several of the victims, along with Heyer’s mother, Susan Bro, were in Hoppe’s courtroom during Fields’s 15-minute appearance. Some were crying, and some gasped when Fields leaned toward a microphone and entered one plea to the entire indictment.

“Not guilty,” he said. Minutes later, he was led away by deputy U.S. marshals.

The Aug. 12 incident, captured on video from numerous angles and viewed worldwide, occurred amid clashes involving hundreds of white supremacists and counterprotesters in the hometown of the University of Virginia. Heyer’s death came after a violent, daylong outpouring of hate. Organizers said the rally was meant to protest the city’s planned removal of a public statue of Confederate Gen. Robert E. Lee.

A photo of Heather Heyer rests among a memorial in Charlottesville last year. (Steve Helber/AP)

In announcing the federal charges June 27, Attorney General Jeff Sessions said, “Today’s indictment should send a clear message to every would-be criminal in America that we aggressively prosecute violent crimes of hate that threaten the core principles of our nation.”

The Justice Department’s action seemed to contrast with President Trump’s less-forceful statements about the Charlottesville violence shortly after it occurred.

Dozens of the rally participants wore red “Make America Great Again” hats and were vocal in their support of Trump. At an afternoon news conference on the day of the riots, the president decried “this egregious display of hatred, bigotry and violence on many sides. On many sides.”

The state charge of first-degree murder against Fields carries a sentence of 20 years to life behind bars. Besides the murder count, Fields faces eight state charges of “aggravated malicious wounding,” which applies when a victim suffers a “permanent and significant physical impairment,” according to the statute.

“It’s like losing an arm or a leg,” Bro said after the hearing, referring to her daughter’s death. “I learn to live with the amputation. I don’t like it, but I’m learning to live with it.”