Mr. Mamdani roundly defeated Andrew M. Cuomo in the Democratic contest, widening his primary-night lead by a significant margin once ranked-choice tabulations were run.

Zohran Mamdani has won a decisive victory in the primary race to become the Democratic candidate for the next mayor of New York City, according to The Associated Press, after building a commanding lead in first-choice results that shook the national political establishment.

The New York City Election board on Tuesday confirmed a stunning victory by mayoral candidate Zohran Mamdani in the Democratic primary, clearing the way for the political upstart to be the party's nominee for the November mayoral election.