The US Justice Department will ask the Supreme Court to overturn an appeals court's recent decision to quash the death penalty for Boston Marathon bomber Dzhokhar Tsarnaev, officials said.
"Our hope is that this will result in reinstatement of the original sentence and avoid a retrial of the death penalty phase," Massachusetts prosecutor Andrew Lelling said in a statement late Thursday.
Tsarnaev, 27, was sentenced to death in 2015 for planting two home-made bombs near the finish line of the race in 2013, killing three people and injuring 264 others.
He has admitted carrying out the attack as a 19-year-old with his older brother, Tamerlan Tsarnaev, who died four days after the atrocity in a gunfight with police.
Lawyers for Tsarnaev had asked for a new trial, claiming that it should not have been held in Boston because the city was so traumatized by the attack.
They also questioned the neutrality of two jurors, who lied during jury selection about whether they'd had conversations about the case on social media.
Last month, the federal appeals court in Massachusetts upheld most of Tsarnaev's convictions but instructed a district court to hold a new penalty-phase trial to determine his fate for crimes that carried the death sentence.
President Donald Trump criticized the decision.