A Metro-North train derailed Sunday morning at Spuyten Duyvil station in the Bronx, the New York Fire Department said.
At least two died, a New York City police source familiar with the investigation and rescue told CNN.
About 100 firefighters are responding to the scene.
Multiple injuries are reported, according to CNN affiliates WABC and WCBS.
Two to five cars came off the track shortly after 7 a.m., fire officials told WCBS. They did not enter the water, the station reported.
Service has been suspended on part of the Hudson Line, Metro-North said on Twitter. (CNN)