One person was killed and another injured after two gunmen reportedly disguised as women attempted to storm the gates of the National Security Agency headquarters. The FBI has confirmed the shooting in Fort Meade, Maryland, was not terrorism-related.

A gunfight broke out after the pair allegedly tried to ram the gates of the agency's building in their Ford Escape. An NSA police officer intervened and killed one of the suspects and seriously injured the second man, according to reports from the Associated Press.

In a separate report from NBC News, the men were dressed as women and a gun and drugs were later found in their stolen vehicle. It remains unclear why the men were trying to gain access into the building.

"FBI Baltimore is investigating a shooting incident which occurred this morning at a gate at the National Security Agency at Fort Meade just off I-295 in Anne Arundel County, MD. The shooting scene is contained and we do not believe it is related to terrorism," an FBI spokesman told IBTimes UK.

She added FBI agents were conducting interviews with witnesses alongside the NSA investigators and other law enforcement agencies. The FBI is also working with US prosecutors in Maryland "to determine if federal charges are warranted".

The NSA has not yet released any further details of the incident. Around 40,000 people work at the facility, which is responsibility for covert communications intercepts.