White House down as power outage hits Washington DC

A power outage struck much of the Washington area today, hitting the White House, the Capitol and the State Department and affecting several thousand people.

Outages stretch from the nation's capital into neighboring Maryland, knocking power out for more than 2,500 people, according to area power companies.

The White House lost power briefly before back-up generators kicked in, restoring lights and computers that were knocked out for several seconds, according to an AFP reporter.

Power at Capitol Hill flickered on and off intermittently but was later restored.

Photos on social media showed crowds being ushered out of Smithsonian buildings as power cuts swept the nation's capital.

Power company Pepco did not say what caused the outage, only that they were investigating the problem.

"Shortly before 1 pm we experienced a dip in voltage in the Washington D.C. area. This was caused by an issue with a transmission line" Pepco posted on Twitter.

"We are currently looking into the cause and will provide more details as soon as we receive an update," it had said earlier.

The Department of Homeland Security said it was "closely monitoring the ongoing power outage affecting parts of Washington."

The State Department went dark in the middle of a press briefing, an AFP reporter said, and the press conference continued briefly without lights.

State Department officials told reporters the power company said electricity could return in the coming hours.

Several metro stations were on emergency lighting, but trains continued to run in the nation's capital.

Metro police said on Twitter "units responding to assist at all stations affected by power outages. No elevator entrapments reported at any station."