SAN DIEGO, CA (WPVI) --The Navy says an initial inspection at Naval Medical Center San Diego found no sign of a gunman or a shooting.
Navy spokesman N. Scott Sutherland said Tuesday that military police had checked Building 26 after a person reported hearing three shots in the basement earlier in the day.
The base remained on lockdown as authorities went from room to room and led personnel out of the facility.
School officials say a lockdown has ended and instruction has resumed at three schools near the medical center.
In addition, TV images showed uniformed Navy personnel walking outside the medical facility. Their hands were in the air and they were being patted down by base police as a precaution.
The Navy hospital previously said on its Facebook page that an active shooter was reported and people were told to run, hide or fight:
"**!ATTENTION!** An active shooter has just been been reported in building #26 at Naval Medical Center San Diego. All occupants are advised to run, hide or fight. All non-emergency response personnel are asked to stay away from the compound, located at 34800 Bob Wilson Drive, San Diego, CA 92134"
A Navy official tells ABC News that a sentry at the medical center received a report around 8 a.m. from someone who claimed they heard gunshots fired in the vicinity of Building 26.
Base security and San Diego police responded to the scene and a shelter in place order was issued.
First responders and Navy Working Dog Units have conducted an initial top down inspection of the building.
The 272-bed, multispecialty hospital and ambulatory complex is located on about 78 acres in the southeast corner of Balboa Park, about 2.5 miles from downtown, according to its website. Center staff is comprised of more than 6,500 military, civilian, contractor and volunteer personnel.
NMCSD personnel deploy to Iraq, Afghanistan, Kuwait, Djibouti and aboard the USNS Mercy, the website said. The facility is affiliated with 19 civilian nursing schools, training more than 400 students per year in clinical rotations.
Information from the Associated press was used in this post.