Robert Bowers, 50, also wounded seven more, including five police officers, after he barged into the Pittsburgh building and opened fire with an assault rifle and other weapons.

Bowers was charged with 63 counts, including hate crimes resulting in death and obstruction of the free exercise of religion resulting in death.

During his weeks-long trial, jurors heard testimony from survivors and evidence of Bowers' antisemitism, including posts attacking Jews made on a far-right website in the months before the 27 October 2018 attack.

At the US District Court in the Pennsylvania city, the jury convicted him of all charges.

Bowers turned a sacred house of worship into a "hunting ground", targeting his victims because of their religion, a prosecutor had told jurors.

Reading the names of each of the 11 victims he killed at the Tree of Life synagogue, prosecutor Mary Hahn asked the jury to "hold this defendant accountable... and hold him accountable for those who cannot testify".

During the trial, a woman recounted how she was shot in the arm and then realised her 97-year-old mother had been shot and killed next to her.

Andrea Wedner told jurors she touched her mother's body and cried out, "Mommy", before officers led her to safety.

Bowers faces death sentence or life in jail

The guilty verdict was not in doubt after his lawyers conceded at the start of the trial that he attacked and killed worshippers at the synagogue.

He could be sentenced to death or face life in prison without parole.

All 12 jurors must vote unanimously in order to sentence Bowers to death with the penalty phase set to last several weeks.

His lawyers had offered a guilty plea in return for a life term in jail but prosecutors refused, choosing instead to take the case to trial and pursue the death penalty.

Most of the victims' families expressed support for the decision.

Prosecutors will try to show that aggravating factors were involved, arguing Bowers carefully planned the attack and targeted vulnerable victims. Most of the victims were elderly.

The defendant's legal team plans to introduce evidence that Bowers has schizophrenia, epilepsy and brain impairments as they try to save his life.