A U.S. federal jury has sentenced the attacker who killed 11 Jewish worshipers at a synagogue five years ago to death. 

The 12-member jury unanimously ruled that Robert Bowers, 50, should be executed for the October 27, 2018, mass shooting in Pittsburgh – the deadliest anti-Semitic attack in U.S. history.

However, President Joe Biden's Justice Department has put a moratorium on federal executions, making it unclear whether the sentence will ever be carried out.

The 50-year-old was in June found guilty of all 63 charges leveled against him, including hate crimes resulting in murder and attempted murder.

The massacre compounded fears of a resurgence of far-right extremists and neo-Nazis across the United States.

"Hate crimes like this one inflict irreparable pain on individual victims and their loved ones and lead entire communities to question their very belonging," said Attorney General Merrick Garland, reacting to the sentence.

"All Americans deserve to live free from the fear of hate-fueled violence, and the Justice Department will hold accountable those who perpetrate such acts," he added.

Wednesday's verdict marks the first time federal prosecutors have sought and won a death sentence during Biden's presidency.

Jewish organizations welcomed the verdict. Michael Masters, chief executive of the Secure Community Network, which provides security advice to American Jewish institutions, said the sentence was "another step on the path to justice."

It "sends a message to violent extremists, terrorists, and anti-Semites everywhere that the United States will not tolerate hate and violence against the Jewish people, nor any people of faith," he added in a statement.

Bowers' trial opened in late April and came amid a rising number of anti-Semitic incidents in the United States, according to the Anti-Defamation League.

In 2022, the U.S.-based Jewish group registered 3,697 acts of harassment, vandalism and assault, a 36-percent increase over the prior year and the highest since it began keeping records in 1979.

The United States is home to around six million Jewish people, according to a 2021 Pew Research Center study.

(With input from AFP)