WASHINGTON — The Agriculture Department says all its offices will be open Thursday after facilities in five states were briefly closed due to an unspecified email threat.

USDA spokesman Matthew Herrick says offices in Hamden, Connecticut, and Leetown, West Virginia, will reopen Thursday with security enhancements. Offices in Colorado, Maryland, North Carolina and Kearneysville, West Virginia, reopened Wednesday after being closed Tuesday.

Herrick said Tuesday that several USDA employees had received an email that raised concerns about the safety of personnel and facilities.

He says the department is continuing to work with the FBI and other law enforcement to investigate the threat.

The facilities that were closed include offices for eight USDA agencies, including the Forest Service and the Food Safety and Inspection Service.