A large section of Manhattan's Upper West Side and Midtown neighborhoods are seen in darkness from above during a major power outage on July 13, 2019 in New York City.

Con Edison apologized on Sunday for a blackout that left 72,000 customers without power for hours in large parts of Manhattan, but the root cause of the outage remained unclear.



The power failure began after a "significant electrical transmission disturbance" impacted multiple circuits, according to a company statement. Con Edison said the blackout was not due to a power overload.

"Con Edison sincerely regrets the power disruption to our customers on the west side of Manhattan last night and will be

conducting a diligent and vigorous investigation to determine the root cause of the incident," the company said.

Con Edison planners and engineers are examining the data and the performance of its equipment and will share their findings with regulators and the public at large, the utility said.

Mayor Bill de Blasio said Sunday that the blackout was not caused by an act of terrorism.