It was unclear whether the shooting occurred on the Manhattan-bound 7 train as it was holding in the station, or on the 90th Street-Elmhurst Avenue platform.
Police have not identified the victim, who was pronounced dead on the platform and was not carrying identification. Officers were still searching for the gunmen, one of whom police described as a heavyset man wearing bluejeans and a blue jacket.
The three men had been on board a southbound 7 train that pulled into the aboveground station just before 12:45 p.m. The conductor heard several shots, police said, then saw the victim lying on the platform.
Police officials were still trying to determine the nature of the dispute that led to the shooting. Investigators were examining video from the station, but it was unclear whether it captured the shooting or the suspects, police said.
A witness wrote in Japanese on Twitter of hearing five to six gunshots and then falling to the floor, fearing the shooting was an act of terror, according to the site’s translation.
The train station was closed after the shooting, police said. Subway officials said trains were running express in both directions.
The Metropolitan Transportation Authority, which operates the subway, referred questions to police.
This article originally appeared in The New York Times.