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.
US President Donald Trump has been briefed on the incident.
“NSA police and local law enforcement are addressing an incident that took place this morning at one of NSA’s security vehicle entry gates. The situation is under control and there’s no ongoing security or safety threat,” an NSA statement said.
After the shooting, authorities closed a major highway in both directions, causing major backups throughout the area during rush hour.