The Naval Medical Center in San Diego has been placed on precautionary lockdown after reports of a potential active shooter.
Officials issued a "code white" on Thursday after a caller reported seeing an armed man inside the facility.
“No shots have been fired. Security is investigating," officials said on Facebook. "As a measure of precaution staff are sheltering in place - staff and patients en route to NMCSD are advised not to come to the hospital until the scene is cleared."
Ambulances, fire trucks and police cars arriving at Naval Medical Center pic.twitter.com/E2I2iBMWvV— Phillip Molnar (@PhillipMolnar) March 24, 2016
The anonymous caller matched the description of a patient seen with a weapon, one security official told USA Today.
In January, an active shooter was also reported at the hospital, however, security officials determined it was a false alarm.