SUITLAND, Md. (AP) – A fire official says a guard at the U.S. Census Bureau headquarters has been shot and critically wounded.

Prince George’s County Fire Department spokesman Mark Brady said in a text message Thursday evening that the guard, who was at one of the campus’s gates, had a gunshot wound to his upper body and was taken to a local hospital in extremely critical condition.

The Bureau of Alcohol, Tobacco, Firearms and Explosives tweeted Thursday night that it was on the scene of “an active shooter incident” at the U.S. Census Bureau headquarters. It was not clear if that was still the case, however.

The FBI is also investigating.

The Census Bureau is located in Suitland, Maryland, a suburb of Washington, D.C.

Thousands of people work on the campus.