At least one person was injured in a shooting outside the entrance to the US National Security Agency (NSA) headquarters in Maryland on Wednesday, according to local media.
The alleged shooter is reportedly in police custody.
A black SUV appeared to have crashed into a concrete barrier surrounding the site, and bullet holes were visible in the vehicle's front windows.
The NSA said the situation was under control, advising motorists that a highway leading to the complex was closed in both direction "due to a police investigation."
"The president has been briefed on the shooting at Ft. Meade," the White House said in a statement.
(With inputs from AFP)