FORT COLLINS, Colo. — Some U.S. Agriculture Department offices in Fort Collins are among those closed around the country Tuesday because of anonymous threats.

A spokeswoman for the General Services Administration, Sally Mayberry, says four buildings used by agriculture department agencies at the Natural Resources Research Center have been closed.

Over 1,000 people from several government agencies work at the campus near Colorado State University. It’s not clear if the closures are also affecting people who work for non-agriculture department agencies.