Shots were fired Tuesday morning at the Pentagon, with at least one bullet striking a window of the Defence Department's massive headquarters building, dpa reported.
No one was hurt in the incident, officials said, but access to the building and nearby roads was temporarily closed after the shots were heard about 5 am. Traffic restrictions were lifted about an hour later, said Steven Calvery, director of the Pentagon Force Protection Agency.
Calvery estimated five to seven shots were fired, likely from a high-powered rifle, but the investigation was ongoing.
Police officers were sent to investigate the sound of gunfire, and access was curtailed to the building, adjacent parking lots and the Pentagon underground station. There were other witnesses who heard the shots and were being questioned, Calvery said.
Police were also investigating shots on Monday that hit the Marine Corps Museum Memorial in Quantico, Virginia, outside Washington. No connection between the two incidents had been established.