NSA shooting: One shot dead for attempting to enter Fort Meade campus gate

At least one man has been killed and another injured during a gun attack at a gate to the U.S. National Security Agency headquarters near Washington.

According to the BBC, the security agency fired on a vehicle after it refused to follow commands and charged a police vehicle blocking the road.

An official said that the men inside the car were dressed as women.

While one of the car's occupants died on the spot, the other was injured and taken to a local hospital.

The incident took place in the morning when at least two people tried to drive the vehicle into the National Security Agency section of the Fort Meade facility.

The NSA said in a statement that the vehicle had refused to obey commands and exit the secure area. The car moved towards the NSA vehicle, which it smashed into as police opened fire on it, the statement said.

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

The Federal Bureau of Investigation (FBI) has taken the lead on the probe.

FBI Baltimore spokeswoman Amy Thoreson said that the agency did not believe that the incident was linked to terrorism.

White House officials said that President Barack Obama had been briefed on the incident.

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

The NSA is a clandestine intelligence agency that collects and analyses electronic signals for US intelligence and counterintelligence purposes.