The primary in staunchly liberal New York is likely to determine who becomes mayor in November's election.

The former governor's loss marks the "biggest upset in modern NYC history," Trip Yang, a political strategist, told the BBC.

"A massive win for Zohran Mamdani that shows that when Donald Trump is President, New York Democrats want to see their leaders fight with enthusiasm and courage, and that's what Zohran showed voters."

In an interview with the New York Times, Cuomo said he was still examining whether he would run in the general election in November on the independent line.