Officials said nothing was found to substantiate the report from one person that shots were fired in Building 26 of the Naval center, not far from Balboa. The building houses barracks, a gym and other administrative offices, according to Naval Capt. Curt Jones.
This did not stop authorities from continuing a sweep of the 78-acre medical center campus before giving a complete all clear, he said.
The incident started around 9 a.m. Pacific when someone reported hearing three shots fired in the basement of the building, which is separate from the main hospital complex, according to Navy spokesman Kevin Dixon.
The report triggered an emergency protocol as military and local police started searching the building while other officers swept the location nearby, forcing traffic away from the spot. The Naval Medical Center also prompted non-emergency personnel to stay away from the building and others already inside to take cover, run or fight.
Investigators are continuing the search and have begun interviewing the person who reported the gunfire, a U.S. official said.
The Naval center is the largest healthcare system in the U.S. military in the western United States. It is surrounded by Balboa Park and rests on 78 acres. The hospital has 272 beds, eight clinics for active duty personnel and nine primary care site for family members.
Nearby locations instituted their own lock-down procedures as a precaution, with restaurants deciding to stay closed until the Navy gave an all clear. This was not ordered by police but instead decisions of the proprietors.
A middle school and two high schools not far from the Naval center did lock down as a precaution, according to the San Diego Unified School District.