Zohran Mamdani, a 33-year-old Muslim socialist, wins New York City mayoral primary

Young socialist candidate Zohran Mamdani closed in on victory in the Democratic mayoral primary in New York City, with the 33-year-old stunning his opponent, former New York governor Andrew Cuomo, in Tuesday's elections.

In what appears to be the left-leaning city's rebuke of the Democratic Party's veteran moderates, Mamdani led with 43 per cent of the vote with 95 per cent of ballots counted, city officials reported.

"Tonight we made history," Mamdani said in his victory speech surrounded by supporters after surging from behind.

"We have won because New Yorkers have stood up for a city they can afford," he added. "A city where they can do more than just struggle."

The 67-year-old Cuomo, a political veteran who was vying to come back from a sexual harassment scandal, told supporters at an election night party: "Tonight was not our night."

He said: "I called him, I congratulated him... he won."

The party's primary contest featured almost a dozen candidates seeking to become mayor of the biggest US city, with a population of more than eight million, which is staunchly liberal.

The contest is ranked-choice, with voters asked to select five candidates in order of preference, and neither Cuomo nor Mamdani claimed the required majority Tuesday.

Zohran Mamdani reacts next to his parents Mahmood Mamdani and Mira Nair and wife Rama Duwaji in New York City. Reuters

With the Democrats reeling nationally from Donald Trump's presidential election win last year, the high-profile city race has done little to calm party nerves.

But Mamdani's upbeat campaign, built with youthful social media savvy and campaign promises to improve the city's affordability, appears to have resonated with voters.

Cuomo stepped down as New York governor four years ago after multiple women accused him of sexual harassment. He was also accused of mismanaging the state's response to the Covid pandemic.

Staunchly pro-Israel Cuomo led in polls for most of the race, with massive name recognition as the son of another New York governor, as well as support from powerful centrist figures including former president Bill Clinton.

Mamdani is backed by the Democratic Socialists of America — the kind of niche, leftist affiliation that might work in the Big Apple but many analysts warn against.

The fact that Mamdani, a Muslim, speaks out for Palestinians and has accused Israel of "genocide" also makes him a prime target for Trump, who is also a New Yorker.

His supporters include two favorite Trump foils — fiery leftist Senator Bernie Sanders and progressive congresswoman Alexandria Ocasio-Cortez, who both congratulated Mamdani.

"Billionaires and lobbyists poured millions against you and our public finance system. And you won," Ocasio-Cortez wrote on X.

Sanders posted: "You took on the political, economic and media Establishment -- and you beat them."

Curtis Sliwa, the Republican candidate, said Mamdani "is too extreme for a city already on edge."

Texas Senator Ted Cruz, a Republican, called on New Yorkers to move to his state, which leans Republican.

"To all my friends in New York who are not Communists: Come to Texas! We love freedom and we're not nuts," he said on social media.

Voters told AFP they saw the ballot as an opportunity to guide party politics.

"I see it as a referendum of the Democratic Party, whether we lean more towards the centrist candidate, who's maybe from a different generation of politicians and people in society, or a younger, left-leaning, more ambitious, idealistic party," voter Nicholas Zantal, 31, said.

Currently a New York state assemblyman representing the borough of Queens, Mamdani stands out for his energetic campaigning style and eye-catching policy proposals that include freezing rent for many New Yorkers, providing free bus service, and universal childcare.

And in a wildly expensive city, where a three-bedroom apartment can easily cost $6,000 a month, his message struck a chord with some.

Voter Eamon Harkin, 48, said prices were his "number one issue."

"What's at stake is primarily the affordability of New York," he said.

But Sheryl Stein, who works in tourism marketing, was skeptical.

"I like youth," she said. But Mamdani having "no experience and no proven track record to run the largest city in this country and one of the largest in the world is pretty scary."

The confirmed winner of the Democratic Party nomination will face several contenders in November, including current Mayor Eric Adams, who is a Democrat but has vowed to run again as an independent. 

Agence France-Presse