Boston marathon bomber Dzhokhar Tsarnaev's lawyers filed a request seeking a new trial Monday, less than two weeks after the 21-year-old was given the death penalty for the attack that took place in 2013, according to the Associated Press.

The motion, filed in the U.S. District Court in Boston did not include any details on what grounds they will argue, saying only that a new trial is "required in the interests of justice." The motion acts as a "placeholder" for a more complete motion to be filed in mid-August, the Huffington Post reported.

Tsarnaev was convicted of 30 charges in the marathon bombing and the events that followed, claiming three lives and injuring more than 260 others. The same jury that convicted him sentenced him to death, according to CBS Local.

At the sentencing last month, Tsarnaev apologized for the suffering he caused. "I am sorry for the lives that I've taken, for the suffering that I've caused you, for the damage that I've done," he said, adding, "I pray for your relief, for your healing," reported USA Today.

During his trial, defense lawyers admitted that Tsarnaev and his brother Tamerlan had planted two pressure-cooker bombs near the finish line of the marathon. Their argument was that Tamerlan orchestrated the attack and requested the jury to give Tsarnaev life imprisonment as opposed to the death sentence.