Jay Jacobs, the chairman of the New York Democratic Party, said on Thursday he will not endorse Zohran Mamdani for mayor of New York City, notably breaking with Gov. Kathy Hochul, who recently announced her support for the Democratic nominee.

In a statement, Jacobs said he had a “positive conversation” with Mamdani, the 33-year-old democratic socialist and Queens assemblyman, soon after the primary, and dismissed what he called “the fear-mongering around him and his candidacy” as “wrong and a gross over-reaction.”

But while Jacobs said he shared Mamdani’s belief that “America’s greatest problem is the continued growth in income disparity in our nation,” the state party chair noted they “fundamentally disagree” on “how to address it.” 

Jacobs, who is Jewish, also cited Mamdani’s staunch opposition to Israel, an issue on which the nominee has recently indicated he has no intention of budging, as a major source of contention.

“Furthermore, as I expressed to him directly, I strongly disagree with his views on the State of Israel, along with certain key policy positions,” Jacobs said of Mamdani, who has vowed to arrest Israeli Prime Minister Benjamin Netanyahu if he is elected and said he would move to terminate a city program to foster partnerships between companies in Israel and New York City, among other positions that have raised concerns among Jewish leaders.

Jacobs did not elaborate on particular policies that Mamdani has proposed, including free bus service, government-run grocery stores, universal childcare and rent freezes, some of which have faced scrutiny from the business and real estate communities.  

He also voiced strong objections to the far-left platform of the Democratic Socialists of America, of which Mamdani has long been a member, saying he did not believe the group “represents the principles, values or policies of the Democratic Party.”

“For those reasons I will not be endorsing Mr. Mamdani for mayor of New York City,” Jacob said in his statement. 

The decision to withhold his support for Mamdani comes as the mayoral nominee has claimed backing from a growing number of mainstream Democratic leaders in New York, most recently Carl Heastie, the speaker of the state Assembly, a prominent holdout who issued his endorsement on Wednesday — days after Hochul made her announcement last weekend. 

Still, some of the state’s top Democratic elected officials, including Senate Minority Leader Chuck Schumer (D-NY) as well as House Minority Leader Hakeem Jeffries (D-NY), have continued to remain on the sidelines, with less than two months until the November election.

In splitting with Hochul, Jacobs, who has long sparred with his party’s left-wing base, joins some lawmakers who have recently said they will not back Mamdani; Reps. Laura Gillen (D-NY) and Tom Suozzi (D-NY), who represent Long Island swing districts targeted by Republicans, have criticized Mamdani’s far-left policies and confirmed this week that they will not be supporting his campaign.

Even as he declined to back Mamdani, the clear front-runner, Jacobs said he would not endorse any other candidates in the mayoral race, according to The New York Times. 

Mamdani’s opponents include Mayor Eric Adams, former New York Gov. Andrew Cuomo — both now running as independents — and the GOP nominee, Curtis Sliwa.

A spokesperson for Mamdani did not immediately respond to a request for comment.