A brief subway power outage in Brooklyn caused extensive delays on most of the lettered lines Tuesday morning.

The Metropolitan Transportation Authority says the power loss occured at DeKalb Ave around 8:30 a.m.

Its impact could be felt as far north as Bedford Park Blvd in the Bronx and as far south as Brighton Beach in Brooklyn. 

Photos and videos posted on social media showed train platforms packed with commuters. 

This was the second outage in three days at the DeKalb Avenue stop, and its impact extended to the B, C, D, F, N, Q, R and W lines. 

Regular service was restored about an hour after the outage.

The MTA said it was a Con Ed issue, with power unable to get to the signals that power subway service.

The Riders Alliance, an advocacy group, said this is unacceptable. Its executive director, John Raskin, teed off on Cuomo.

"Subway service is starting to resemble the notorious dysfunction of the 1970s, and riders are asking: where is Governor Cuomo? Governor Cuomo shows up to open the Second Avenue Subway, but he’s missing in action for the day-to-day disaster that transit riders are experiencing," the statement reads. "Subway riders leave for work these days not knowing if or when they will actually get there.  Any one incident can be explained, but in the aggregate it’s clear that subway service is deteriorating and that riders are increasingly miserable."

On April 21, there was another widespread power outage during the morning rush that extended to practically all of the lettered lines. That, too, was pinned on Con Edison.

The governor's spokesman, Jon Weinstein, alluded to that in his statement, saying, "The two most recent subway disruptions were caused by ConEd system failures, which is exactly why the Governor directed a state investigation into the last incident and why today he has directed the MTA to meet with ConEd to identify the cause and propose a real and improved response plan for the future. Blasting out press releases devoid of facts is cheap and unconstructive and we should expect more from so called transportation experts."