Reagan National Airport lost power late Wednesday night due to an outage from Dominion Power and interrupted airport operations for more than an hour, airport officials said.

The entire airport lost power about 9:45 p.m. and within a few minutes, back-up generators restored electricity to FAA operations, security and other vital airport functions, said Andrew Trull, a spokesman for the Metropolitan Washington Airports Authority.

Two Dominion power lines feed the airport and both appeared to malfunction, but power officials did not provide a cause to the airport officials, Trull said.

Flights continued to land and depart, if planes had already been boarded. However, the airport jet bridges use electricity so some passengers could not immediately deplane.

The Dominion Power website reported that utility officials had dispatched a crew to investigate outages in the area. The website said 273 customers were affected but it was unclear whether that number included the airport.

The majority of the evening flights had arrived or taken off, but about two dozen flights were affected, Trull said.

Dominion Power and airport officials reported that power was restored about 11 p.m. Utility officials said they continued to investigate the cause of the outage late Wednesday.