A bomb threat was called in to the Walter Reed National Military Medical Center, forcing a building to be closed for three hours at the facility outside Washington.
Someone phoned in a threat minutes before 9 a.m. Wednesday, saying a bomb would detonate about an hour later in the center's America building, which contains a group of clinics, a military official said.
The official spoke on condition of anonymity because he was not authorized to publicly release information about the incident.
The building was swept for explosives, and none was found, the official said. The building reopened at 1 p.m.