As soon as Rabbi Eric Gurvis of Newton got a news alert on his phone Saturday morning about the shooting at Tree of Life Congregation in Pittsburgh, he texted a rabbinical school classmate who leads a different synagogue nearby.
“I’m sure this is unnerving,” Gurvis said he wrote to Rabbi Jamie Gibson of Temple Sinai in Pittsburgh.
“Damn straight,” Gibson texted, said Gurvis, rabbi emeritus at Temple Shalom of Newton.
The violence erupted as many Jews gathered Saturday morning for Shabbat services, and some learned of the shooting after spending hours in prayer. The gunman, identified by authorities as Pittsburgh resident Robert Bowers, opened fire during a baby-naming ceremony.
Eleven adults died, Pittsburgh Public Safety Director Wendell Hissrich said. Six people were injured, including four police officers. The shooting is being investigated as a hate crime.
Bowers had expressed anti-Semitic views on social media, where he also criticized President Trump, The New York Times reported.
Robert Trestan, regional director for the Anti-Defamation League New England, said representatives from the Boston Police Department and the FBI’s Boston office reached out to him following the shooting.
Officer Stephen McNulty, a Boston police spokesman, said in an e-mail that the department has increased patrols around synagogues in the city.
A spokeswoman for the FBI’s Boston office said it is contacting community leaders.
“Synagogues are very busy places on Shabbat and also [Sunday] when there is religious school and events and weddings. It’s important that local law enforcement not just see this as something that’s happening in another part of the country but as an event that affects the sense of security that people have in Boston,” Trestan said.
The shooting, he said, is a “horrific reminder of what happens when anti-Semitism is played out to the greatest extent.”
“You walk in the door of a synagogue and you feel safe and, regrettably, now one of the safest places seems to be one of the most vulnerable, which is the place people go to pray,” Trestan said.
President Trump condemned the violence, saying ‘‘there must be no tolerance for anti-Semitism in America.’’
He also said the outcome might have been different if the synagogue had an armed security officer.
‘‘This is a case where, if they had an armed guard inside, they might have been able to stop him immediately,’’ Trump said.
Trestan said “creating a fortress is not the solution.”
“We have to focus on reducing anti-Semitism and hate across the country,” he said. “There’s security in place for houses of worship. At the same time, we need to tackle the problem at its roots.”
State and city leaders, including Governor Charlie Baker, Mayor Martin J. Walsh, and Attorney General Maura Healey, posted messages on Twitter expressing condolences.
“I am horrified by the mass shooting in Pittsburgh, and my thoughts are with the victims, their families and the first responders,” Baker said in a tweet. “We must work together to overcome this evil and violence.”
Cardinal Sean P. O’Malley, archbishop of Boston, offered prayers on Twitter.
“On this Sabbath day, when our Jewish brethren observe a day of rest and worship, we embrace them in their anguish,” he said. “We also are praying for the local police officers impacted during this senseless and despicable act of violence. May God bless all those lost and the injured.”
Rabbi Elaine Zecher, senior rabbi at Temple Israel of Boston, said she was leading services when she learned about the shooting.
“I can tell you many congregants were in Torah study,” she said. “There was a real sense of sadness and loss that they felt viscerally.”
Zecher said she grew up near Pittsburgh and her mother lives in the city.
“This is a call that we cannot ignore anti-Semitism. We can’t ignore hate and we can’t foster it because it emerges in ways that are awful,” she said.
Gurvis said the synagogue shooting and the case of Cesar Sayoc, the Florida man accused of sending pipe bombs to prominent Democrats, are symptoms of the hateful rhetoric promoted by Trump and other political leaders.
He said he recently attended a meeting at Newton City Hall, where faith leaders discussed ways to combat the vicious tone of today’s political discourse. The gathering was organized by Newton Mayor Ruthanne Fuller, Gurvis said.
“I don’t know how we dial it back, but it has to be dialed back,” he said. “We need our leaders to get real about what’s tolerable and what’s not tolerable.”
Jack Nusan Porter, a sociologist at the Davis Center for Russian and Eurasian Studies at Harvard University and a former rabbi, said his nephew is an Orthodox rabbi in Squirrel Hill, the Pittsburgh neighborhood where the shooting occurred.
He said he planned to try to reach him Saturday evening because his nephew observes Shabbat and doesn’t answer his phone during the Sabbath.
Trump’s rhetoric condones, perpetuates, and instigates violence, Porter said.
“When the president opens up the floodgates of hatred, it affects everything,” he said. “If you let loose the dogs of hatred and intolerance, and if the president talks that way, then weaker minds are going to take it a step further.”