Police arrest man accused of throwing firecrackers near White House

A man is taken into custody by uniformed Secret Service Police on Pennsylvania Avenue outside the White House on Monday, Sept. 16, 2013, in Washington. Evan Vucci / AP

Police have arrested a man accused of throwing firecrackers over a fence near the White House Monday evening.

Officials tell NBC News that it was not clear why the man was using the fireworks but that he was not considered a threat.

The man threw the firecrackers over a fence at the White House North Lawn, prompting reports of loud popping noises within earshot of the president's residence. 

The arrest came just hours after a man identified as 34 year-old Aaron Alexis killed 12 people in a shooting spree at a Washington D.C. naval facility just miles from the White House.

The District of Columbia remained on edge after the massive shooting at the Navy Yard, with some schools and Senate offices at the nearby United States Capitol on lockdown for part of the afternoon as law enforcement attempted to rule out a possible second suspect.