Most of the anti-Semitic incidents in New York have not been perpetrated by jihadists or far-right extremists, but by young African-American men, Mr. Greenblatt said. Local leaders said that phenomenon grows out of tension in areas where longstanding African-American and Jewish communities have been squeezed by gentrification.

“You have this mixture of African-Americans and Hasidic people, and then you have gentrification,” said Gil Monrose, an African-American pastor at Mt. Zion Church of God 7th Day who lives in Crown Heights. “All of this is colliding in Crown Heights and it leads to young people committing crimes where they live.”

“Sometimes people want to blame different groups for the fact that they are being priced out of the neighborhood, but the Jewish community is not to blame for that because the Jewish community is being priced out too,” he said. “That’s why they went to Jersey City.”

In November, the Anti-Defamation League expanded an anti-bias education program it started in Brooklyn in 2018 with a goal of bringing it to 40 schools. Eric L. Adams, the Brooklyn borough president, praised the program when the expansion was announced.

“Since extremist, hate-filled rhetoric has become awakened and stoked across this country — particularly in Crown Heights right here in Brooklyn — this unacceptable behavior is increasingly becoming the norm for some,” Mr. Adams said in a statement.

The rise in anti-Semitic attacks has been not limited to Brooklyn.

Jeff Katz, the treasurer of the Stanton Street Shul, a small Orthodox synagogue on the Lower East Side of Manhattan, said that he was riding the subway one day last fall when another passenger erupted at him.

“He was saying, ‘Why aren’t you looking at me?’” said Mr. Katz, who wears a yarmulke. “And I thought, ‘We’re on the subway, I don’t want any part of this. Then he started saying, ‘What? Do you think you’re superior, Jew boy?’”