A gunman has shot and wounded a security guard at the headquarters of the US Census Bureau just outside of Washington DC.
The Prince George’s County Fire Department said the guard was taken to hospital in critical condition.
Local media is reporting that the gunman has barricaded himself inside the headquarters.
An unknown number of employees are stuck inside the building, which has been sealed off.
Thousands of people work at the Census Bureau campus but the incident apparently began after normal working hours.
Live television images showed a large police presence with dozens of officers in military-style gear stationed outside the campus.
The local police department directed reporters to contact the FBI for further information.