Travis Air Force Base in California is under a security alert due to a "real world security incident," the base said in a Facebook post.
The Air Force base had a training exercise planned for Wednesday and Thursday, but this is not related to it, according to CBS Sacramento.
When asked if the situation is related to the training exercise, the official response on Facebook was: "The current security incident is not associated with the scheduled base exercise."
Several people have posted on the Facebook page that there is an "...active shooter situation at the shopping center on base," but base officials have neither confirmed nor denied that.
The public is being asked to stay away from the base while emergency responders do their job.
A "shelter in place" warning was sent out by the base in a Twitter post.
KCRA reporter Kevin Oliver posted on Twitter: "People in buildings near the BX at Travis AFB have been told to "shelter in place" Told they can't leave their buildings."
Travis Air Force Base is home the 60th Air Mobility Wing.
UPDATE: Travis Air Force Base officials posted the following update at 6:05 p.m. (Montana time): "Travis Air Force Base emergency personnel responded to reports of gun shots at the Base Exchange. However, no shooter was found. The base is no longer under lockdown."
Loudspeaker outside Travis Air Force Base: Real World...LockDown. pic.twitter.com/WALDZNTFPs— stevelarge (@largesteven) June 14, 2017