A shooting erupted on Wednesday outside the headquarters of the National Security Agency (NSA), a secret intelligence agency responsible for global US electronic eavesdropping in the suburbs of Washington, the White House confirmed.

At least one person has been injured in the shooting, officials said. “We can confirm there has been one person injured and we don't know how the injuries occurred,” an NSA spokesman told AFP.

The local ABC affiliate put the number of injured at three and said a suspect was arrested. The NBC News aired aerial images of what appeared to be police surrounding a man on the ground in handcuffs outside the NSA facility in Fort Meade, Maryland.

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 Fort Meade,” the White House said in a statement. “Our thoughts and prayers are with everyone that has been affected.“

A law enforcement source said the Federal Bureau of Investigation (FBI)'s Baltimore office was handling the investigation but it was “too soon to tell” whether it was an attack. They are “still trying to ascertain the facts,” the source said.

Known as the “Puzzle Palace,” the NSA is the nerve centre for the US electronic espionage as well as the main protector of US communications and information systems from cyber attack.

The agency was thrust into the spotlight in 2013 when former contractor Edward Snowden leaked details of its global surveillance programs, including its collection of data on Americans. Snowden has been charged with violating the Espionage Act and theft of government property. He now lives in exile in Russia.

The NSA was the scene of a similar incident in March 2015 when police fired on an SUV, killing the driver and wounding a passenger after they failed to obey orders to stop at its heavily guarded entrance. In that incident, the two men in the Ford SUV were dressed in women's clothes “but not in an attempt to disguise themselves from authorities,” an FBI spokeswoman said at the time.