The self-described neo-Nazi convicted of killing Heather Heyer by ramming his car into a crowd protesting a white supremacist rally in Charlottesville, Virginia in 2017 will learn on Friday whether he will spend the rest of his life in prison.

Prosecutors urged a federal judge in Charlottesville to impose the harshest possible sentence on James Fields, 22, after he pleaded guilty to federal hate crime charges connected from the Aug. 12 attack, which also injured 19 people.

Fields attacked a crowd of counter protesters in the college town at the end of two days of rallies by avowed white nationalists, who marched first with torches and later with medieval-style shields.

It proved a critical moment in the rise of the "alt-right," a loose alignment of fringe groups centered on white nationalism and emboldened by President Donald Trump's 2016 election.

Trump was criticized from the left and right for initially saying there were "fine people on both sides" of a dispute between neo-Nazis and their opponents. Subsequent alt-right gatherings failed to draw the crowds of size that assembled in Charlottesville.

Ahead of Friday's sentencing hearing, prosecutors noted that Fields had long espoused violent beliefs, and less than a month before the attack posted an image on Instagram showing a car plowing through a crowd of people captioned: "you have the right to protest but I'm late for work."

Even after the attack, Fields remained unrepentant, prosecutors said, noting that in a Dec. 7, 2017 phone call from jail with his mother, he blasted Heyer's mother, Susan Bro, for her activism after the attack.

"She is a communist. An anti-white liberal," Fields said, according to court papers filed by prosecutors. He rejected his mother's plea to consider that the woman had "lost her daughter," replying, "she's the enemy."

Fields pleaded guilty in March under a deal with prosecutors who agreed not to seek the death penalty.

Fields, a resident of Maumee, Ohio, was photographed hours before the attack carrying a shield with the emblem of a far-right hate group. He has identified himself as a neo-Nazi.

Fields' attorneys suggested he felt intimidated and acted to protect himself.

They asked a judge only to sentence him to less than life in prison, without specifying a number, seeking mercy citing his relative youth and history of mental health diagnoses.

He will be sentenced separately on state charges next month.