According to several news outlets, the Bob Wilson Naval Hospital in San Diego is on lockdown following a tip from an anonymous caller indicating there was an active shooter inside a building and that other gunmen were possibly involved.
USA Today notes:
The call matched another report of a patient seen with a weapon, according to the official who was not authorized to speak publicly. All personnel were ordered to shelter in place and police were responding to the scene.
The medical center is … is located on the grounds of Balboa Park … and provides advanced treatment facility as well as serving as a major teaching and research center. About 500 people work there.
On Thursday, security personnel found and a bullet on the floor in one of the buildings, the official said. A caller reported a patient with a gun and then hung up.
Police with dog teams are at the hospital investigating, the official said.
A similar report at the same facility was phoned in to authorities in January but turned out to be a false alarm.
This is a developing story that will be updated as new information becomes available.