At least four people have been killed and 63 people were injured after five passenger rail cars derailed in the Bronx area of New York.
Of the injured 11 are believed to be in a critical condition in hospital.
The New York Fire Department reported the train derailment happened on Palisades Avenue near the Spuyten Duyvil railway station, next to the Hudson River.
The train was about half full at the time of the crash, with about 150 passengers on board, New York State's Metropolitan Transportation Authority said.
Eye-witnesses tweeted images of the scene showing rail cars on their sides on the banks of the river.
Police and other rescue workers were searching for survivors along the shoreline and the waterway in a wooded area where the Hudson and Harlem rivers meet.
The train derailed on a large curved section of track at 7.20am (12.20pm Irish time) in New York about 100 meters north of the station.
The train was a diesel with seven cars. It was on the north end pushing the rail cars southward.
This train was not scheduled to stop at the Spuyten Duyvil station and was headed toward Grand Central terminal in Manhattan, the MTA said
After touring the scene, New York Governor Andrew Cuomo said officials from the National Transportation Safety Board were travelling to the scene and would conduct a thorough investigation.