Rep. Adriano Espaillat, D-N.Y., has lost his primary to a challenger backed by New York Mayor Zohran Mamdani, NBC News projects, in a major victory for the progressive wing of the party.

Community organizer and activist Darializa Avila Chevalier, a 32-year-old member of the Democratic Socialists of America, defeated Espaillat, 71, after casting him as an insufficient fighter for the working-class residents of the upper Manhattan district.