Boston Marathon bomber Dzhokhar Tsarnaev addressed a federal court for the first time on Wednesday, admitting his guilt for committing the 2013 terrorist attack and apologizing to the victims.

"I am sorry for the lives I have taken, for the suffering that I have caused you, for the damage I have done, irreparable damage," said the 21-year-old convicted terrorist before the packed courtroom packed, according to NBC News.

Earlier this year, Tsarnaev was found guilty of 30 charges and sentenced to death for his role in the Boston Marathon bombings on April 15, 2013. His older brother, Tamerlan, died three days after the blasts during a shootout with police.

"In case there is any doubt, I am guilty of this attack, along with my brother," Tsarnaev said while standing at the defense table, Reuters reports.

"You told me how horrendous this was, this burden that I put you through," Tsarnaev said. "I wish that four more people had a chance to get up there, but I took them from you."

Tsarnaev also made note of the Muslim holiday Ramadan and asked for forgiveness for his heinous act.

"I ask Allah to have mercy upon me, my brother and my family," he said. "I ask Allah to bestow his mercy upon those who are here today."

Before Tsarnaev apologized for killing four people and wounding 264 others in the deadly attack and its aftermath, two dozen people shared delivered victim impact statements at the hearing.

Rebekah Gregory, who lost her left leg at the race, addressed Tsarnaev with a strong and direct words.

"Terrorists like you do two things in this world. One, they create mass destruction, but the second is quite interesting," Gregory said. "Because do you know what mass destruction really does? It brings people together. We are Boston strong and we are America strong, and choosing to mess with us was a terrible idea. How's that for your victim impact statement?"

Survivor Jeanne-Marie Parker also spoke before the court, telling the terrorist, "I hope you own all this grief and anguish for the rest of your life," reports The New York Times.

During the hearing, U.S. District Judge George O'Toole also formally sentenced the killer to death.

"As long as your name is mentioned, what will be remembered is the evil you've done. What will be remembered is that you murdered and maimed innocent people and that you did it willfully and intentionally. You did it on purpose," O'Toole told Tsarnaev.