A power outage at a Manhattan subway station caused widespread delays and service changes during the morning rush Friday, prompting Gov. Andrew M. Cuomo to order an investigation.

It was not immediately clear what caused the outage at the Seventh Avenue-53rd Street station at about 7:25 a.m. The MTA was still investigating with Con Edison at the scene in the afternoon, a spokeswoman said.

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Service was restored on most lines at about 11:30 a.m., after temporary generators were set up at the station, but extensive delays continued for hours, the MTA said.

Commuters took to Twitter to fume.

“Commute from Hell! Over 1 hour!” one user posted with a picture of a packed subway car.

Cuomo called the outage “completely unacceptable.”

“I am directing the Department of Public Service and the MTA to conduct an immediate investigation into the Con Edison equipment failure, the cause of the outage and the response to it,” he said in a statement.