Two brothers and a husband and wife were among those killed. Six people were injured, including four policemen.
The suspect, Robert Bowers, 46, is in custody and faces 29 criminal counts in what is thought to be the worst anti-Semitic attack in recent US history.
Mayor Bill Peduto said this was the “darkest day of Pittsburgh’s history”.
President Donald Trump has called the attack a “wicked act of mass murder”.
Who are the victims?
The ages of the 11 victims ranged from 54 to 97. They are:
- Joyce Fienberg, 75
- Richard Gottfried, 65
- Rose Mallinger, 97
- Jerry Rabinowitz, 66
- Cecil Rosenthal, 59
- David Rosenthal, 54, brother of Cecil
- Bernice Simon, 84
- Sylvan Simon, 86, husband of Bernice
- Daniel Stein, 71
- Melvin Wax, 88
- Irving Younger, 69
What is the latest from Pittsburgh?
The names were read out by officials at a press briefing on Sunday morning.
Mayor Peduto said: “To the victims’ families and friends – we will be here to help you through this horrific episode – the darkest day of Pittsburgh’s history. We as a society are better than this, we know that hatred will never win out.”
Officials gave some details about the attack, revealing that the gun suspect used three Glock 57 handguns and an AR-15 assault rifle and made statements regarding genocide and a desire to kill Jewish people.
The suspect is still in hospital, in fair condition with multiple gunshot wounds, but is scheduled to make his first court appearance at 13:30 local time (17:30 GMT) on Monday.
Officials said there was nothing to indicate he had any accomplices.
One injured officer was released from hospital on Saturday, another should be released on Sunday, with the other two needing more treatment.
The remaining two injured people are members of the congregation.
What are the charges?
The 29 charges were announced in a statement issued by the US Attorney’s Office of the Western District of Pennsylvania:
- Eleven counts of obstruction of exercise of religious beliefs resulting in death and 11 counts of use of a firearm to commit murder during and in relation to a crime of violence. These can carry the death penalty
- Four counts of obstruction of exercise of religious beliefs resulting in bodily injury to a public safety officer
- Three counts of use and discharge of a firearm during and in relation to a crime of violence
How did the shooting unfold?
On Saturday morning, worshippers had gathered at the Tree of Life synagogue for a baby naming ceremony during the Sabbath.
Squirrel Hill has one of the largest Jewish populations in Pennsylvania and this would have been the synagogue’s busiest day of the week.
Police said they received first calls about an active shooter at 09:54 local time (13:54 GMT), and sent officers to the scene a minute later.
According to reports, Bowers, a white male, entered the building during the morning service armed with an assault rifle and three handguns.
The gunman had already shot dead 11 people and was leaving the synagogue after about 20 minutes when he encountered Swat officers and exchanged fire with them, FBI agent Robert Jones said.
The attacker then moved back into the building to try to hide from the police.
He surrendered after a shootout.
The crime scene was “horrific”, Pittsburgh’s Public Safety Director Wendell Hissrich told reporters. “One of the worst I’ve seen, and I’ve [worked] on some plane crashes. It’s very bad.”
What do we know about the gunman?
US media said he had shouted “All Jews must die” as he carried out the attack.
Social media posts by someone with the name Robert Bowers were also reported to be full of anti-Semitic comments.
FBI special agent Bob Jones told a press conference that Bowers did not appear to be known to authorities prior to the attack.
‘Grief and hurt’
In the dwindling light, and with the cold autumn rain falling, hundreds gathered in front of the 6th Presbyterian church just a few streets away from the Tree of Life Synagogue.
Holding their candles, they sang the Jewish prayer of healing.
The elders in the community had wanted to wait a day before holding the vigil, but the young people said no – they wanted an immediate chance to share their grief and voice their hurt.
Fifteen-year-old Sophia Levin declared that she was a different Jew today to the one she was yesterday. Anti-Semitism, she said, had been something she thought happened elsewhere and in earlier times; but now she knew it was right here, right now.
Some of these young people have been involved in the student gun control movement that sprang up after the Parkland shooting earlier this year.
One of them, Rebecca Glickman, told the crowd that gun control was needed now more than ever.
She told me that an anti-Semite with a gun is more dangerous than an anti-Semite without a gun, so that’s a good place to start.
What has been President Trump’s reaction?
He described the gunman as a “maniac” and suggested the US should “stiffen up our laws of the death penalty”.
“These people should pay the ultimate price. This has to stop,” he said.
Trump said he would visit Pittsburgh soon and had ordered US flags at government buildings to be flown at half-mast until 31 October.
He added that the shooting had “little to do” with US gun laws. “If they had protection inside, maybe it could have been a different situation.”
But Mayor Peduto, a Democrat, said: “I think the approach that we need to be looking at is how we take the guns, which is the common denominator of every mass shooting in America, out of the hands of those that are looking to express hatred through murder.”
What about other reaction?
Pennsylvania Governor Tom Wolf said in a statement that the incident was an “absolute tragedy” and that such acts of violence could not be accepted as “normal”.
Pope Francis said after his Angelus prayer in Saint Peter’s Square: “We are all, in truth, wounded by this inhuman act of violence.”
Jonathan Greenblatt, the head of the Anti-Defamation League (ADL), a Jewish non-governmental organisation that fights anti-Semitism, said he was “devastated”.
“We believe this is the deadliest attack on the Jewish community in the history of the United States,” he said in a statement.
Israeli Prime Minister Benjamin Netanyahu said he was “heartbroken and appalled”.