Authorities responded to a shooting outside the National Security Agency campus at Fort Meade, where police surrounded a handcuffed man after a black vehicle ran into a barrier.
Fort Meade garrison spokeswoman Cheryl Phillips confirmed one person was injured in the shooting outside the base and was taken to hospital.
The NSA released no immediate information, the FBI said it was sending people to the scene.
An image taken from a WRC-TV helicopter shows a police and fire department response outside one of the facility’s secure vehicle entry gates.
WRC said bullet holes could be seen in the vehicle’s front window, and several air bags were deployed.
A federal official said the incident was not linked to terrorism.
The NSA said a vehicle tried to enter the spy agency’s campus in Maryland without authorisation.
The statement also said weapons were fired during the incident but it does not appear that any injuries were caused by gunfire.
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