Logo of National Security Agency (Reuters photo)
A shooting erupted when a vehicle tried to ram an entrance gate to the US National Security Agency outside Washington, media reports said on Monday.
There were conflicting reports of up to two casualties.
Video imagery showed a crash-damaged police vehicle and a civilian vehicle outside a main gate of the super-secure headquarters of the NSA, the US intelligence agency that conducts electronic surveillance worldwide.
CNN reported that police in Anne Arundel, Maryland said one person was killed and another injured in the incident, but provided no other information.
Other reports said two people were injured in the incident.
There was no immediate comment from the NSA or the Pentagon.