The Navy Yard, located less than a mile south of the U.S. Capitol, was placed on lockdown Thursday following an unconfirmed report of an active shooter, WUSA reports.
There are no immediate report of casualties inside the 41-acre facility, which was the scene of a mass killing by a lone gunman in 2013.
Police source tells WUSA reporter Nikki Burdine that Navy security has reported two shooters, but there has been no official confirmation of any gunman siighted.
The U.S. Navy said on Twitter that a lockdown and shelter-in-place is in effect, but said no incident had yet been confirmed.
U.S. Park Police, U.S. Marshals and Homeland Security officers quickly responded to the scene and local roads were closed.
The Navy yard is located on the Anacostia River, south of the National Mall. The nearby U.S. Department of Transportation building was also placed on lockdown as a precaution.