A self-described socialist has won New York City's Democratic mayoral primary.
Zohran Mamdani is a 33-year-old state lawmaker - and ran a campaign that was laser-focused on the high cost of living.
Slickly produced social media videos set out his vision of free buses, free childcare, new apartments and a higher minimum wage - paid for by new taxes on the rich.
Mr Mamdani, who entered the campaign as a virtual unknown, was ahead of Mr Cuomo 43.5% to 36.4% with nearly 95% of ballot scanners reporting, according to the city's elections board.
He declared victory as he addressed his supporters, saying: "Today... with the vision of the city that every New Yorker can afford, we have won."
He promised to reject President Donald Trump's policies and "to govern our city as a model for the Democratic Party."
If elected when voters head to the polls in November, he would be the city's first Muslim mayor.
The primary result is a blow for former New York governor Andrew Cuomo, who was attempting to make a political comeback from a sexual harassment scandal.
He had been a firm favourite throughout the race because of his deep experience, but Mr Mamdani had won the support of the party's progressive wing.
Current mayor Eric Adams is set to run as an independent following an uproar over his indictment on corruption charges.
Mr Cuomo confirmed he had conceded to his Democratic rival, adding: "We are going to take a look and make some tough decisions. Tonight is his night."
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Votes are still being counted - and the outcome of this race could indicate the type of leader Democrats are looking for during Donald Trump's second term.
Mr Mamdani attracted endorsements from prominent progressives including Representative Alexandria Ocasio-Cortez and Senator Bernie Sanders.
But critics have argued that he lacks the experience to handle crises, with Mr Cuomo claiming he was unqualified during the campaign.
Voters turned out in a heatwave to have their say, with temperatures exceeding 37C (100F) on Tuesday.
(c) Sky News 2025: Zohran Mamdani wins New York City's Democratic mayoral primary in shock
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