The Buffalo supermarket gunman had to be removed from the courtroom during his sentencing after a man rushed at him during the victim statement portion of the proceedings.
The member of the audience who rushed at white supremacist Payton Gendron was restrained by officers.
Gendron was sentenced on Wednesday to life in prison without parole.
In November, Gendron pled guilty to several charges, including murder and domestic terrorism motivated by hate. The charge of terrorism meant an automatic sentence of life behind bars.
The now 19-year-old killed 10 Black people during the mass shooting at Tops Friendly Markets on 14 May last year. The killing was motivated by racist conspiracy theories Gendron had found online.
“You don’t know what we’re going through,” a man yelled while officers escorted him from the room, according to the Associated Press.
Family members spent several minutes calming each other following the incident.
Just before the incident occurred, Barbara Massey Mapps denounced Gendron for the murder of her sister, Katherine Massey, 72.
“I want personally to choke you,” Ms Mapps said. “Your little punk a** decided to come here to kill Black people.”
Ms Mapps was yelling and gesticulating at Gendron when a man quickly approached the gunman but was held back by a number of officers before he was able to reach him.
The sentencing was restarted after a break lasting around 10 minutes. Judge Susan Eagan had Gendron return to the courtroom, telling people in the room to “conduct ourselves appropriately”.
“I understand that emotion, and I understand the anger, but we cannot have that in the courtroom,” the judge added.
The widow of security guard Aaron Salter has shortly before been speaking about why she and her family were wearing black and red.
“Red for the blood that he shed for his family and for his community, and black because we are still grieving,” Kimberly Salter said in the courtroom as Gendron looked on.
Those affected by the shooting spoke at the sentencing, with some condemning Gendron while others quoted the bible and said they were praying for him.
Some slammed him for his targeted attack on an area with a lot of Black residents, far away from Gendron’s hometown, which is almost entirely white.
Celestine Chaney was killed in the shooting. Her only child, Wayne Jones Sr, told Gendron, “you’ve been brainwashed”.
“You don’t even know Black people that much to hate them. You learned this on the internet, and it was a big mistake,” he said.
“I hope you find it in your heart to apologize to these people, man. You did wrong for no reason,” he added.
Tops Friendly Market staff member Christopher Braden was shot in the leg. He said, “the visions” from the shooting “haunt me in my sleep and every day”.
At one point, Gendron was seen crying. During the shooting, he wore body armour and a helmet with a camera live-streaming the shooting.
He used a legally purchased semiautomatic rifle that he later illegally modified to be able to use high-capacity magazines.
He specifically targeted Black customers and employees, and shot 13 people, only three of which survived.
Separately, Gendron also faces charges on the federal level that could lead to the death penalty if the Department of Justice chooses to pursue that course, while the death penalty isn’t an option under New York state law.
In December, his defence lawyer said that Gendron was willing to also enter a guilty plea in federal court to avoid a death sentence.
“I cannot express how much I regret all the decisions I made leading up to my actions on May 14,” Genrdon said in court, according to CNN.
“I did a terrible thing that day. I shot and killed people because they were Black. Looking back now, I can’t believe I actually did it. I believed what I read online and acted out of hate. I know I can’t take it back, but I wish I could, and I don’t want anyone to be inspired by me and what I did,” he added.
