Police say that they are responding to reports that at least one gunman is inside a Navy Yard in Washington, DC.
*Update: NBC news report that no shots were fired at the US Navy Yard in Washington DC earlier today, but the base remains in lockdown. Officials say that the first sweep by police buildings has found no evidence of an armed individual. A second check by armed officers is being carried out as a precaution. Official sources say that the person who made an emergency call that sparked todays massive police response is being interviewed by officers.
TV news footage has shown dozens of police vehicles and scores of police officers at the scene.
One employee inside the facility says alarms are sounding around the site and buildings are currently in lockdown, according to WUSA
who also report that Navy security sources say police are currently looking for two gunmen at the Navy Yard.
The US Navy have said on Twitter that buildings in the complex are on lockdown, but no incidents can be confirmed yet.
People have been evacuated from buildings near Navy Yard building
The sprawling military complex in the southeast part of the city was the scene of a mass shooting in 2013, when Aaron Alexis went on a killing spree at the Navy Yard killing 12 people. He was eventually shot dead by police. This was the second-deadliest shooting at a US military base after the Fort Hood shootings in 2009.
Updates to follow.