Image copyright Reuters Image caption Several police agencies were on the scene

One man has been killed and another was seriously wounded after a shooting at a gate to the US National Security Agency headquarters near Washington.

NSA officers fired on a vehicle that refused to follow commands and charged a police vehicle blocking the road.

An unnamed official told the Associated Press that the men inside the car were dressed as women.

One of the car's occupants died on the scene, while the other was injured and taken to a local hospital.

The incident began shortly after 9:00 local time (14:00 GMT) when at least two people attempted to drive the vehicle into the National Security Agency section of the Fort Meade facility.

The NSA, in a rare public statement, said that the driver refused to obey an NSA police officer's commands to exit the secure area.

The vehicle charged toward the NSA vehicle, which it smashed into as police fired on it, the statement said.

The statement does not mention anyone other than NSA police firing a weapon.

Image copyright ABC Image caption The collision happened at the crossroads

Image copyright AP

Helicopter footage of the scene recorded shortly after the incident showed two cars - one a police vehicle and the other a black vehicle with no insignia - with extensive damage in a junction that had been roped off near the security gates leading to the NSA.

The cars appeared to have collided and debris was strewn across the intersection. A white cloth appeared to cover something beside the black vehicle.

The FBI has taken the lead on the investigation.

"We do not believe it is related to terrorism," FBI Baltimore spokeswoman Amy Thoreson told the BBC.

President Barack Obama was briefed on the incident, according to White House officials.

Image copyright AP Image caption Aerial footage showed debris strewn across the junction shortly after the incident

The large Fort Meade campus, located about 30 minutes outside Washington, is home to about 40,000 military and civilian personnel, plus many members of employees' family.

The facility houses the US Cyber Command, the US Defense Information School and other agencies, in addition to the NSA.

The NSA is a clandestine intelligence agency, charged with collecting and analysing electronic signals for US intelligence and counterintelligence purposes.

The agency rose to prominence after Edward Snowden leaked thousands of the agency's documents in 2013.

Earlier this month the FBI arrested a man for firing shots that damaged the building from a nearby highway.

There is no indication the two incidents are linked.