Navy Yard's metro station is OPEN. Green line is running fine, according to Metro spokesperson.
Dan Stessel of Metro: Buses running slow in the area.
WTOP's Dick Uliano is on the scene. Tune in to WTOP for his report.
WTOP's Dick Uliano reports that the gunman is still at large.
A ground stop is in effect at Reagan National Airport due to the incident at the Washington Navy Yard.
WTOP's Dick Uliano says there is an enormous police response. Helicopter circling above.
There are "bewildered employees" trying to get to work still, unaware of the threat, reports WTOP's Dick Uliano.
Another ambulance just responded to the scene, Dick Uliano reports. Several ambulances have already responded.
UPDATE: Ground stop at Reagan National Airport is for departures
WTOP's JJ Green is at the scene. Tune in to WTOP to hear his latest reports.
D.C. police confirm to WTOP there are at least 5 victims; there are reports elsewhere of 7 at Washington Navy Yard
CBS News' Cami McCormick reports suspect at Navy Yard is described as having multiple weapons.
A source told WTOP's JJ Green that the shooting took place on fourth floor of Building 197 Washington Navy Yard.
DC police confirm there are at least 10 shooting victims.
UPDATE: D.C. police confirm at least 10 victims in Washington Navy Yard shooting
A U.S. Park Police helicopter hovered over the Navy Yard earlier today and appeared to drop a basket or a stretcher with a person onto the roof, according to the Associated Press.
U.S. Navy confirms to WTOP there have been fatalities at the Washington Navy Yard. NBC is reporting 4.
Associated Press: President Barack Obama is getting frequent briefings on a shooting at the Washington Navy Yard.
The White House says the president had several briefings about the unfolding situation by senior aides.
The Navy says shots were fired Monday morning at the Naval Sea Systems Command headquarters, where about 3,000 people work. The Navy reports several people were injured.
The White House says Obama directed his team to stay in touch with the Navy, FBI and local officials.
UPDATE: Ground stop has been lifted at Reagan National Airport
Associated Press, citing Defense official: Navy Yard shooter 'contained,' not in custody
It is a "dynamic situation" at the Navy Yard, reports WTOP's Dick Uliano.