San Diego: A report of an active shooter and shots fired at the US Naval Medical Center in San Diego triggered a heavy law enforcement response on Tuesday but was apparently unfounded, Navy officials said.
A lone witness reported hearing three shots at about 8 am PST (1600 GMT) in the basement of a building at the sprawling medical center, the officials said.
Police interviewed the witness and continued to clear the building into Tuesday afternoon but there was no sign of foul play.
"We did an initial clearing of the building and found nothing that would indicate any kind of dangerous situation,” Navy Captain Curt Jones, commanding officer of the Naval facility, told a news conference.
California and the United States remain on edge after a married couple inspired by Islamist militants shot and killed 14 people last month in San Bernardino, about 100 miles (160 km) north of San Diego.
The city is home to the US Navy's Pacific Fleet.
Seven law enforcement agencies, including US Marshals, SWAT teams and an armored car from the San Diego County Sheriff's Department were involved in the response to the reported shooting.
Police with rifles and dogs searched the building where the shots were reported, as workers filed out with their hands in the air.