The deadly attack at a Pittsburgh synagogue will “not break us”, religious leaders said, after the shooting of 11 people.

Rabbi Jonathan Perlman, who helped hide people during Saturday’s shooting, said: “What happened yesterday will not break us. It will not ruin us.” The rabbi, along with other congregation leaders, spoke at an interfaith memorial service on Sunday.

The suspected gunman, Robert Bowers, is due to appear in court later on Monday.

Scott Brady, US Attorney for the Western District of Pennsylvania, says he is seeking the death penalty against the suspect. The final decision will depend on US Attorney General Jeff Sessions.

Survivors of what is believed to be the worst anti-Semitic attack in US history recalled taking refuge and hiding in storage rooms to avoid the roaming attacker. One congregation leader said their training in active-shooter situations had helped save lives, and that Rabbi Perlman helped lead worshippers to storage rooms where they could hide.

The 11 victims were named on Sunday and included a husband and wife, and a woman aged 97.

Mayor Bill Peduto said that this was the “darkest day of Pittsburgh’s history”.

When the suspect was detained after a shootout, he reportedly told Swat officers he wanted “all Jews to die”.

Robert Bowers, 46, now faces 29 criminal charges. He is still in hospital being treated for multiple gunshot wounds.

Social media site Gab, which has been criticised for serving as an outlet for the far-right, has now gone offline after it was revealed the suspect had been an active member.

Three congregations were reportedly meeting at the Tree of Life synagogue in the Squirrel Hill district of Pittsburgh on Saturday morning. Members of the New Light congregation were meeting in a basement area, Carl Solomon, 81, a congregation member who turned back from the synagogue but had spoken to survivors, told the New York Times.

Richard Gottfried, 65, and Daniel Stein, 71, were in the kitchen and both were shot dead. Congregation co-president Stephen Cohen told the paper there was “no place to hide” there. He said Rabbi Perlman had shepherded two other people into a storage room, although one, Melvin Wax, 88, chose to later open the door and was shot dead.

Mr Cohen said “everyone froze but Rabbi Perlman”. He told the Associated Press news agency that leaders had taken part in active-shooter drills “and I think that’s what ultimately saved the people who were saved”.

Worshipper Joseph Charny, 90, said he saw a man appear at the door and heard shots. He told the Washington Post: “I looked up and there were all these dead bodies.” He said he and two others hid in an upstairs storage room until it was safe to come out.

Speaking to CNN on Monday morning, Rabbi Jeffrey Myers said: “I never thought this could happen at my synagogue, ever.” He said security would be a top concern as the community rebuilds. “I will not let hate close my building.”

The victims were named on Sunday as Joyce Fienberg, 75; Rose Mallinger, 97; Jerry Rabinowitz, 66; Cecil Rosenthal, 59, and his brother David, 54; married couple Bernice Simon, 84, and Sylvan Simon, 86; and Irving Younger, 69. Tributes have been pouring in from those who knew the victims. Myron Snider described his friend Melvin Wax as a “sweet, sweet guy” and unfailingly generous. Ben Schmitt, a patient of Jerry Rabinowitz, said the family medical practitioner was “kind and funny… [he] completely personified the term ‘bedside manner'”.

Cecil and David Rosenthal were described as “kind, good people with a strong faith and respect for everyone around”.

One injured officer was released from hospital on Saturday, another was due to be released on Sunday, with the other two needing more treatment.

Robert Bowers was armed with three Glock handguns and an AR-15 semi-automatic rifle. He owned them legally, a law enforcement officer told the Associated Press. Officers arrived after receiving calls about an active shooter at 09:54 local time (13:54 GMT) on Saturday and encountered the suspect as he was trying to leave.

The gunman fired at them and ran upstairs. As Swat officers searched for victims, the gunman opened fire on them and injured two. The suspect was detained after being wounded in an exchange of fire with officers.

Officials said the gunman had made statements regarding genocide as well as a desire to kill Jewish people.