Inbound and outbound flights were bogged down for over an hour in the US capital's primary airport, as it experienced a complete power outage. Stranded travelers have been posting images of the sudden blackout on social media.

Late Wednesday evening, the airport's official account tweeted the management was aware of an "airport-wide" power outage and was investigating its cause.

We are aware of an airport wide power outage and investigating. Updates to follow. (950pm) — Reagan Airport (@Reagan_Airport) August 16, 2018

Confused passengers shared photos and videos of the airport's halls, plunged into darkness by the outage. Announcers were reportedly saying the facility was running on auxiliary power, but judging by the images, the lighting was minimal. One user said luggage belts were not running, either.

Power outage at @Reagan_Airport; only minimal lighting, no displays. I asked flight staff if this happens sometimes; they said they've never seen anything like it. #ReaganAirport#PowerOutagepic.twitter.com/mVZ6eIL1bQ — Samuel Breslow (@sdkb42) August 16, 2018

Power out at Reagan Airport? pic.twitter.com/kn5uUmJlle — Errington Thompson (@ecthompsonmd) August 16, 2018

The electricity just went out at Reagan National Airport and folks are wandering around trying to find their stranded bags on the stalled luggage belt by phone light. Infrastructure week? pic.twitter.com/iMUAV3ufiy — Heather Timmons (@HeathaT) August 16, 2018

Mandatory credit: Jason Cambridge.

A Metropolitan Washington Airports Authority spokesperson said the outage was caused by an issue at Dominion Energy, the company supplying power to the airport, as cited by NBC Washington. The spokesperson also said most flights had taken off for the night and any traffic disruption would not be significant.

Power still not on at @Reagan_Airport. There are now emergency vehicles and distinctive smoke visible out the window. #PowerOutage#ReaganAirportpic.twitter.com/bU3vmYSatK — Samuel Breslow (@sdkb42) August 16, 2018

The airport later tweeted that flights were operating, but slowed down by unpowered mechanical systems. Lighting was being provided to some areas via backup generators.

Generator backup power is providing lighting to several areas of the terminal. Updates to follow. (10:35pm) pic.twitter.com/SjdBsUxGfu — Reagan Airport (@Reagan_Airport) August 16, 2018

Power was restored about an hour after the blackout began.

11:13pm: Power is restored to the airport and systems are coming back online. Some flights may be delayed. Thank you for your patience. — Reagan Airport (@Reagan_Airport) August 16, 2018

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