The Saturday morning rituals were still under way at a synagogue in quiet Squirrel Hill when the shots rang out.

The streets were empty, as usual, but inside the nicely kept brick houses of this well-to-do neighbourhood, the centre of Jewish life in Pittsburgh, residents faced the inevitable question - do I know anyone?

Many probably did, or at least knew someone who did.

"You wouldn't expect it," said 30-year-old Nathan Rittri, who lives just a few houses from the Tree of Life Congregation, where the deadly shooting took place. "It's very shocking because the neighbourhood is so loving and calm."

More than a quarter of Pittsburgh's 50,000 Jewish adults and children live in Squirrel Hill, according to the Jewish Federation of Greater Pittsburgh, one of the largest Jewish populations in Pennsylvania.

Several temples from different Jewish denominations, kosher restaurants and local shops form what has been called a "vibrant oasis" of Judaism in the city.

And so, when a gunman opened fire at a local synagogue, many felt that not only their religion was being attacked, but their own little haven.

"It's a tight-knit community, everyone knows everyone," said Adam Hertzman, the federation's marketing director. "The whole Jewish community is shocked, [but] Jewish Pittsburgh is so close together, like a family, it will not change that."

The attack - the darkest day of Pittsburgh's history, according to Mayor Bill Peduto - happened as worshippers gathered in a drizzly morning in different rooms at the congregation, home to three different synagogues. The larger one, Tree of Life, was set up in 1864.

The suspect, 46-year-old Robert Bowers, stormed the building and shot indiscriminately. During the attack, he reportedly shouted "All Jews must die".

"I always knew there were people who hated Jewish people," said 16-year-old student Spencer Lieberman, who avoids wearing Jewish symbols in public, including his necklace with the Star of David. "But I never imagined anyone would do something like this."

Eleven people, whose ages ranged from 54 to 97, were killed in the attack, including a couple and two brothers.

Six others were injured, including four police officers who engaged in a gun battle with the suspect, and two members of the congregation.

But for many in Squirrel Hill, and probably across the country, this is more than just tragedy coming to a small, close community.

The attack happened amid a perceived rise in hate-related crimes nationwide and at the end of a particularly tense week in which more than a dozen explosive devices were sent to critics of President Donald Trump.

Some have blamed the president himself for stirring divisions, claims he denies. He called the attack a "wicked act of mass murder".

Mr Hertzman, who used to worship at the synagogue attacked and knew two of the dead, said: "We've certainly seen that anti-Semitism is on the rise across the US. I don't know if it's increased in Pittsburgh or we're just more aware of that."

The gunman had posted anti-Semitic content on social network Gab under the username "onedingo", and the bio on his account, now suspended, read: "Jews are the children of Satan".

Hours before attacking the synagogue on International Religious Freedom Day, he criticised refugee aid group Hebrew Immigrant Aid Society (HIAS) and said he could not "sit by and watch my people get slaughtered".

"This shouldn't be happening," said 54-year-old resident Dan Berger. "Divisions have been big in the country. We should all be Americans and all these differences are dividing our country."

Mr Bowers faces 29 criminal charges, including obstruction of exercise of religious beliefs, a hate crime, and using a firearm to commit murder. All of these can carry the death penalty.

Throughout Sunday, dozens of residents and others brought flowers and candles to Tree of Life's entrance. They were adamant that the attack would not change this place.

"[The attacker] was an anti-Semitic man but he seemed to be a hateful man," said 34-year-old Molly Butler, who came with her children, Mikey and Lily, aged nine and six.

"Hate is hate, is terrible and it doesn't have any place in our country, city or Squirrel Hill."

Ms Butler's family of Orthodox Jews only found out about the shooting in the evening, as they do not use any electronic device, she said. They carried placards thanking the police for keeping "the Jews in [their] neighbourhood safe".

"You're going to see an outpouring of love and support and a strengthened community. Not just the Jewish community but Pittsburgh as a whole," she said. "This has touched all of us."