A fire underneath New York City's Harlem River bridge cut off commuter train services into and out of Grand Central Terminal Monday.

Initial reports suggested it was caused by an electrical transformer, a spokesman for the city's Office of Emergency Management said.

No one was injured and the cause was still being investigated, a fire department spokesman said.

A thick plume of smoke rose from the Harlem River bridge connecting Manhattan and the Bronx at 138th Street, suspending service on the Metro-North railroad that serves commuters north of the city.

The fire consumed piers below the bridge and inspectors were trying to determine if the intense heat damaged the steel or electrical conduits of the railroad.

The fire, which lasted two hours before being extinguished, took place about 5 miles north of the United Nations, which was celebrating its annual General Assembly.