“Appreciated the call from [Trump],” Newsom tweeted. “Working with state, local, and federal officials on today’s horrific shooting at the Chabad of Poway synagogue.”
Newsom added: “We all must call out hate — against any and all communities — wherever it lives.”
While Trump and Newsom have been at odds long before the latter took office in Sacramento earlier this year - lambasting each other in speeches and on social media over issues ranging from immigration to high-speed rail projects – the two appear to have laid down their differences, at least briefly, in the wake of Saturday’s tragedy.
Police say 19-year-old John Earnest opened fire inside the synagogue near San Diego as worshippers celebrated the last day of Passover, killing one woman and wounding the synagogue's rabbi and two others Saturday, authorities said.
Trump and other elected officials decried what they called an anti-Semitic attack six months to the day after since 11 people were killed at a Pittsburgh synagogue in the deadliest assault on Jews in U.S. history.
Shortly after fleeing, Earnest called 911 to report the shooting, San Diego Police Chief David Nisleit said. When an officer reached him on a roadway, "the suspect pulled over, jumped out of his car with his hands up and was immediately taken into custody," Nisleit said.
Lori Kaye, 60, of Poway was killed in Saturday's shooting, Rabbi Yonah Fradkin, executive director of Chabad of San Diego County, said in a statement. The injured were identified as Rabbi Yisroel Goldstein, Noya Dahan, 8, and Almog Peretz, 34, he said.
The sheriff said the wounded were in stable condition at local hospitals.
A person identifying themselves as John Earnest posted an anti-Jewish screed online about an hour before the attack. The poster described himself as a nursing school student and praised the suspects accused of carrying out deadly attacks on mosques in New Zealand last month and at Pittsburgh's Tree of Life synagogue Oct. 27.
California State University, San Marcos, confirmed Earnest was a student on the dean's list and said the school was "dismayed and disheartened" that he was suspected in "this despicable act."
There was no known threat after Earnest was arrested, but authorities boosted patrols at places of worship as a precaution, police said.
Trump offered his sympathies Saturday, saying the shooting "looked like a hate crime."
"Our entire nation mourns the loss of life, prays for the wounded and stands in solidarity with the Jewish community," Trump said later at a rally in Wisconsin. "We forcefully condemn the evils of anti-Semitism and hate, which must be defeated."
He praised law enforcement's "incredible response" and singled out the off-duty Border Patrol agent who "bravely returned fire and helped disrupt the attack and saved so many lives."
Newsom said he joins the community in grief.
"No one should have to fear going to their place of worship, and no one should be targeted for practicing the tenets of their faith," he said.
The Associated Press contributed to this report.