Just after midnight, Zohran Kwame Mamdani was sworn in as New York City's first Muslim mayor in a modest ceremony held in a historic subway station under City Hall.

The oath was administered by New York state Attorney General Letitia James, a fellow Democrat and a close Mamdani ally. "Congratulations, Mr. Mayor," she said, to cheers.

A much larger public ceremony will be held later on New Year's Day on the steps of City Hall, with Vermont Senator Bernie Sanders — one of Mamdani's political mentors — and New York Rep. Alexandria Ocasio Cortez expected to take part.