The rabbi of a prominent Manhattan synagogue slammed Zohran Mamdani as a “danger to the security of the New York Jewish community” — as he urged congregants to back Andrew Cuomo for mayor instead.

“I believe Zohran Mamdani poses a danger to the security of the New York Jewish community,” Rabbi Elliot Cosgrove, of the renowned Park Avenue Synagogue on the Upper East Side, said during his Saturday sermon.

He said Mamdani refuses to denounce the phrase “Globalize the Intifada,” denies Israel’s legitimacy as a Jewish state, has vowed to arrest Israeli Prime Minister Benjamin Netanyahu and cited his “thrice-repeated accusations of genocide” against Israel in Gaza at last week’s mayoral debate.

“For these and so many other statements … he is a danger to the Jewish body politic of New York City,” Cosgrove said.

Cosgrove’s appeal to congregants came a week before the nine days of early voting were set to kick off. 

The faith leader, in a subsequent interview with The Post on Monday, said his criticism of Mamdani “had to be said.”

Cosgrove noted that he never weighed in on a mayor’s race during his 18 years leading the synagogue, adding, “It’s not my style” to stump from the pulpit.

But he said he could not stay silent when the welfare of the Jewish community was at stake. 

Speaking during Shabbat services, Cosgrove suggested congregants back ex-Gov. Cuomo, running as an independent, for mayor in the November 4 election.

He said a vote for Republican candidate Curtis Sliwa guarantees Democratic nominee and front-runner Mamdani’s election.

“A vote for Sliwa, whatever his merits, is a vote for Mamdani,” Cosgrove said.

“There is a path to victory. No one should sit this one out. We must turn out to vote.”

Mayor Eric Adams, who recently said he won’t run for re-election, addressed Park Avenue Synagogue congregants Friday night, and expressed concern about Mamdani. He also later spoke privately with Cosgrove, a source said.

Adams said he will remain a staunch ally of the Jewish community after his term expires as a fellow New Yorker, a source who heard his speech said.

Cuomo took note of Cosgrove’s takedown of rival Mamdani.

“Powerful words by Rabbi @elliot_cosgrove of @parkavenuesyn #SayNoToZo #VoteforCuomo,” he posted on X Monday, along with footage of the rabbi’s speech.

Park Avenue Synagogue, a conservative sect founded in 1882, has many influential congregants. 

Designer Ralph Lauren and family attend the synagogue, as does CNN anchor Kate Bolduan and Broadway actor Ben Platt, according to reports.

Former New York Jets owner Leon Hess’ celebrity-packed funeral was held there.

Cuomo, Mamdani and Sliwa are set to face-off for the second and final time Wednesday at 7 p.m. during a debate hosted by NY1.

The early voting period begins on Saturday, and New Yorkers have until October 25 to register to cast their ballots.

The Post reached out to the Mamdani campaign for comment.