WEB EXTRA VIDEO: Navy Yard Shooting

By CBS News

Published 09/16 2013 10:25AM

Updated 09/16 2013 10:49AM

WASHINGTON -- (CBS)   As many as 10 people have been shot at the Washington Navy Yard on Monday morning, and at least three and as many as six of those victims died from their wounds, federal and local officials told CBS News.

A gunman was neutralized, officials said, and security personnel are searching for a second gunman, although there has been no corroboration so far as to whether a second gunman exists.

A helicopter lifts a person off the roof as police respond to the report of a shooting at the Navy Yard in Washington, Dc on September 16, 2013.

/Getty Images

An official told CBS News the number of victims could be higher because it is a "chaotic scene." Officials have not offered publicly an exact assessment of the health of the victims.

It is also not clear whether neutralized gunman is a member of the Navy.

Police and emergency crews gathered Monday morning outside the heavily-guarded Naval Sea Systems Command Headquarters building, where the shooting was reported. To enter the building, visitors and employees must pass several checkpoints, leading to some speculation this may have been a coordinated attack by an insider or multiple insiders.

The Navy said about 3,000 people work in the building. People inside the building have been directed to stay in place.

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