Decision comes weeks after Robert Bowers found guilty of killing 11 worshippers at Tree of Life synagogue in 2018.

A United States jury has ruled that a gunman who fatally shot 11 people at a synagogue in Pittsburgh in 2018 is eligible to face the death penalty.

The decision on Thursday comes about a month after a jury found Robert Bowers guilty of 63 criminal counts related to the Tree of Life synagogue attack, including hate crimes resulting in death and obstruction of the free exercise of religion resulting in death.

Both prosecutors and defence lawyers are now set to make arguments on whether Bowers should be put to death, and the jury will then go back and deliberate.

In US federal cases, a unanimous vote is required to sentence a defendant to death. If jurors are unable to reach a unanimous decision, Bowers will instead be sentenced to life in prison without the possibility of release.

Bowers, 50, a truck driver from the Pittsburgh suburb of Baldwin, killed members of three congregations in the attack on October 27, 2018. He also wounded two worshippers and five police officers.

Bowers had ranted on social media about his hatred of Jewish people before the shooting and told police at the scene that “all these Jews need to die”. He told psychologists who examined him afterwards, including as recently as May, that he was pleased with what he did.

During the trial, prosecutor Mary Hahn said Bowers had a long record of engaging with and promoting anti-Semitic and white supremacist content online.

“He is filled with hatred for Jews,” she said. “That is what propelled him to act.”

Bowers’ defence team, meanwhile, argued that he had adhered to the “great replacement” conspiracy theory, which falsely states that white people in the US are being systematically replaced by non-white immigrants.

His lawyers argued that while the attack was reprehensible, it was based on “nonsensical and irrational” beliefs and not anti-Jewish hatred.

The trial included wrenching testimony from survivors.

“I just laid on the floor and didn’t move in case he was there or was coming back. I didn’t want him to know I was alive,” Andrea Wedner, whose 97-year-old mother, Rose Mallinger, was killed in the attack, recounted to the jury.

During the penalty phase of the trial, prosecutors said that Bowers had shown the necessary intent and premeditation to qualify for the death penalty. They presented witnesses and evidence to show he carefully planned the attack for months.

US Attorney Eric Olshan argued that Bowers was not delusional, but that he “just believes things that are repugnant”.

Defence lawyers for Bowers have argued he suffers from major mental illness, including schizophrenia, and therefore lacks the necessary level of intent to justify the death penalty.

They had offered a guilty plea in return for a life sentence, but prosecutors refused, opting instead to take the case to trial and pursue the death penalty.

If jurors determine Bowers should be put to death, it would be the first federal death sentence imposed during the administration of US President Joe Biden.

Despite Biden campaigning on a pledge to end capital punishment, federal prosecutors continue to pursue the death penalty in some cases.