"We received word that our base emergency personnel responded to reports of gun shots," staff sergeant Nicole Leidholm, a spokeswoman at Travis Air Force Base, told AFP. "However, no shooter was found. The base is no longer on lockdown."
Leidholm said the alarm was sounded at approximately 3:15 pm local time, prompting officials to urge all personnel, dependents and retirees at the sprawling facility to seek shelter or avoid the base.
The base is located some 55 miles (90 kilometers) northeast of San Francisco.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)