Explosion Near White House - Took Place During Security Sweep, As Obama Leaving White House

Van explosion, according to @runpacers “@will_sweet1: So this fire just broke out right outside the White House.... pic.twitter.com/0oWqvwbWDu”
— Philip Crowther (@PhilipinDC) March 7, 2015

NBC says it was a small explosion:

It appears a small explosion and fire broke out at a food vendor location near the White House, while there was a lockdown and a Secret Security sweep of the area. Photos from Will Sweet show heavy smoke from one of the food locations in the 400 block of 15th Street, Northwest on Saturday morning. D.C. fire officials said the fire was extinguished and one person was evaluated on the scene, but not transported to a hospital. The White House press pool was out on the South Lawn for the departure of President Barack Obama and his family around the same time as the fire. Secret Service moved the press back into the White House and initiated a lockdown of the building. During a sweep of the area, a K-9 unit hit on a vehicle in the 1600 block of Constitution Avenue. The White House remains on lockdown while authorities check out the vehicle. It is unknown if the two events are related despite their proximity in time.