Jonathan Greenblatt, the CEO and national director of the Anti-Defamation League (ADL) said the shooting at a southern California synagogue on the last day of Passover proves “anti-Semitism is a virulent and vicious problem right now in America.”

Greenblatt made the comment on “America’s Newsroom” on Monday, shortly after he landed in New York City from San Diego. He said he flew to San Diego on Saturday, shortly after authorities said a 19-year-old man armed with an assault-type rifle opened fire inside a synagogue as worshipers were celebrating the last day of Passover, killing a woman and injuring three others.

Lori Gilbert-Kaye, 60, died of injuries she sustained in the shooting at the Chabad of Poway, located in a suburb near San Diego. Three others were wounded and transported to the hospital, including the synagogue’s rabbi, Yisroel Goldstein. Goldstein was injured after suffering a gunshot wound to his hand. Noya Dahan, 8, and her uncle, Almog Peretz, 34, were also injured. Dahan was hit by shrapnel in the face and leg. Peretz was reportedly shot in the leg as he was trying to protect children in the synagogue. All three have been discharged from the hospital.

“I got there on Saturday afternoon and spent the evening praying with Rabbi Goldstein’s family and spent Sunday morning (with) Lori Kaye's (family)" Greenblatt said on “America’s Newsroom.”

When asked how they are doing he answered, “It’s very, very hard.”

He added, “They are thankful for the fact that only one person was killed, but the loss of even one life is an enormous tragedy. And this, six months to the day of the shooting at the Tree of Life (Synagogue in Pittsburgh), the most violent anti-Semitic attack in American history and on the day, yesterday, when we kick off Holocaust memorial week. So looking at all these things come together reminds us that anti-Semitism is a virulent and vicious problem right now in America.”

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Authorities identified the alleged shooter in Saturday's attack as 19-year-old John Earnest. He was taken into custody following the shooting.

San Diego County Sheriff Bill Gore said FBI and homicide agents have interviewed Earnest and they are looking into his social media accounts.

He said they are investigating reports that the 19-year-old, who had no prior contact with law enforcement before Saturday, had written an anti-Jewish screed online.

Gore said Earnest is also being investigated for a possible connection to arson that caused property damage at Dar-ul-Arqam mosque in Escondido, Calif. last month. No injuries were reported in that fire.

“He is a white supremacist. His manifesto clearly identified with a series of conspiratorial ideas that have been used to persecute Jews as well as other minorities for a long time,” Greenblatt said.

He added, “He’s someone whose bigotry, it may start with the Jews in terms of anti-Semitism, but anti-Semitism never ends with the Jews. It’s a disease. Hate will consume us all if we don't respond to it.”

Greenblatt said there is a series of things that need to happen to combat the hate.

“First and foremost, our leaders need to lead and speak out clearly and consistently not only after a crisis but every day about the values that we hold dear,” said Greenblatt.

“Secondly, I think social media has a special responsibility here. Silicon Valley needs to not just innovate for financial returns, but it needs to work those algorithms to protect all of its users because Facebook and YouTube and these other platforms really are the front line today in fighting hate. It's the place where white supremacists and many other kinds of bigots spread their poison.”

NEW YORK TIMES APOLOGIZES AGAIN FOR 'OFFENSIVE' TRUMP, NETANYAHU CARTOON THAT 'INCLUDED ANTI-SEMITIC TROPES'

On “America’s Newsroom,” Greenblatt also responded to a cartoon of President Trump and Israeli Prime Minister Benjamin Netanyahu that was called offensive because of "anti-Semitic tropes."

The New York Times Opinion section issued a second apology Sunday over the cartoon, which showed an apparently blind Trump wearing a pair of sunglasses and being led by a dog depicted as Netanyahu. The dog had a Star of David collar. The cartoon appeared in the paper’s opinion section next to a column penned by Thomas Friedman.

"We are deeply sorry for the publication of an anti-Semitic political cartoon last Thursday in the print edition of The New York Times that circulates outside of the United States, and we are committed to making sure nothing like this happens again," the opinion section tweeted Sunday.

"Such imagery is always dangerous, and at a time when anti-Semitism is on the rise worldwide, it's all the more unacceptable," continued the apology, which was widely shared on Twitter.

The new apology said that the decision to run the syndicated cartoon was made by a single editor working without adequate oversight.

The political cartoon was criticized globally by numerous social media users, who said the Times' first statement was inadequate.

“Let's not call it a cartoon. It’s propaganda pure and simple,” said Greenblatt in response.

He added, “It doesn't belong in any mainstream American publication, certainly not the New York Times.”

He added, “It reminds us that anti-Semitism comes in many forms. We were just talking about new media, you also see it in traditional media. Sometimes it’s over chants of ‘Jews will not replace us’ in Charlottesville. Sometimes it’s thinly veiled like this supposedly criticism of Israel. But it’s anti-Semitism pure and simple.”

Greenblatt said he felt compelled to tweet in reaction to the drawing because “we feel so strongly about this” but added, “the ADL doesn't just tweet, we act. So we’ve been engaged with the management at The New York Times.”

Greenblatt said, “I spoke to management at the Times before that second apology and I explained to them clearly, an apology is not enough. We need action and accountability. That means policies and procedures need to change. That means they need to not only own up to what they've done, they need to get out front of this.”

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“Just Imagine the man who murdered Lori Kaye in San Diego County on Saturday, he was influenced -- we know from his manifesto -- by this idea of Jewish control, Jewish manipulation, exactly the kind of image that The New York Times printed just a few hours earlier.”

The Associated Press contributed to this report.