Washington CNN  — 

Widespread power outages hit across Washington, D.C. on Tuesday, affecting government and privately-owned buildings and the city’s public transit rail system intermittently early in the afternoon.

The power outage, which is affecting about 2,000 customers in the Washington area was caused by a small explosion and fire at a power substation in southern Maryland, according to local and U.S. officials.

Charles County Fire & EMS dispatched firetrucks to the Southern Maryland Electric Cooperative’s Ryceville power substation shortly after 12:45 p.m. on Tuesday, when 9-1-1 calls came in reporting the incident, said Bill Smith, the Fire & EMS department’s public information officer. The station is partly operated by PEPCO, the electricity utility in Washington, D.C.

Fire officials extinguished the “small fire” that sparked off at a transformer at the power station in about 35 minutes, Smith told CNN. There were no injuries, he added.

“The power has been shut down [at the station]. Any fires that we had are out,” he said.

By 2 p.m., most power was back on, SMECO said. It explained the outage on Twitter.

Smith added that the incident was likely an accident and there is no indication of arson or a terrorism connection and County fire officials have handed over the scene to PEPCO and SMECO.

“At this time, there is no indication that this outage is the result of any malicious activity,” a Department of Homeland Security official told CNN, adding that the department is monitoring the power outage.

The outage struck everything from the White House to the State Department, where government employees and reporters saw lights and power flicker out.

Adm William Gortney, the NORAD commander, said power in the nation’s capital is just one example of the “fragile” infrastructures – including banking, rail, aviation and cyber threats – that “causes me great concern.”

“We try and mitigate them as best we can,” he said, noting that backup systems kicked in as expected on Monday.

Power at CNN’s D.C. bureau twice flickered off and on early in the afternoon.

The power went out during the daily State Department briefing, with Deputy Spokesperson Marie Harf using a phone light to continue taking questions from reporters. Power remained off for the State Department as of 1:15 p.m., though most other affected buildings appeared to have power restored within seconds of it going out.

A spokesman for Pepco, the city’s major electric utility, told CNN that the company is aware of the outages and is investigating the source of the problem.

Capitol Hill Police spokeswoman Kim Schneider said power has been restored to all buildings on Capitol grounds.

“As Pepco attempts to resolve the problem, we are prepared for any further power outages and/or surges that may occur,” she said.

The outage also forced the Smithsonian to evacuate four of its museums in D.C.

The power outages did not appear to affect major buildings outside of the District besides the power substation. Neither of the city’s two major airports, which are both located in Virginia, were affected.

A White House spokesman says the power outage that affected many parts of the city also affected the White House complex. The White House was on a backup generator and is now back on normal power.

In addition to the briefing room, power went out very briefly in the West Wing and other portions of the White House. Building maintenance workers ​were circulating through office space ensuring power had been restored, which it had.

A spokesperson for the city’s Metro rail system says 13 stations are on backup power, meaning no escalators or elevators working – but lights are on and trains are running.

The outages gave some familiar D.C. locations an unfamiliar appearance, including the National Portrait Gallery, which tweeted a lights-out photo from inside the building.

CNN’s Eric Bradner, Jim Sciutto, Shimon Prokupecz, Kevin Liptak, Matthew Hoye and Jamie Crawford contributed to this report.