FAIRFIELD, Calif. -- Travis Air Force Base lifted a lockdown Wednesday after being under a security alert due to a "real world security incident," the base said in a Facebook post.

Travis Air Force Base emergency personnel responded to reports of gun shots at the Base Exchange. However, it was... Posted by Travis Air Force Base on Wednesday, June 14, 2017

CBS Sacramento, citing a Travis Air Force spokesperson, reports the active shooter situation started at the Base Exchange, but later said no shooter was ever found and it was a false alarm.

The base is located in Solano County, about 40 miles southwest of Sacramento.

Travis Air Force Base in Fairfield, Calif., seen in this file image. They are reporting a "real world security incident" on Wed., June 14, 2017. CBS Sacramento

The public was asked to stay away from the base while emergency responders did their job. A shelter in place warning was sent out by the base in a Twitter post.

Security alert @Travis60AMW. Shelter in place. Lock doors/windows. Await further info. Follow Travis Facebook page for updates. — Travis AFB Official (@Travis60AMW) June 14, 2017

Fairfield Police said it didn't respond to the incident and deferred to the base.

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Reporter from CBS Sacramento posted a video to Twitter where you can apparently hear "real world" and "lock down" being broadcast over loudspeakers:

Loudspeaker outside Travis Air Force Base: Real World...LockDown. pic.twitter.com/WALDZNTFPs — stevelarge (@largesteven) June 14, 2017

Beale Air Force Base in Yuba County -- which is a little more than 80 miles north of Travis Air Force Base -- was not on lockdown, CBS Sacramento reported.

"There was a security exercise underway at the base and somebody took that to be an active shooter and they went from there," said U.S. Rep. John Garamendi, who was briefed on the situation.

The false alarm came on a day marked by violence.

In Virginia, a gunman wounded Rep. Steve Scalise and several others during practice for a baseball game featuring congressional Republicans.

James T. Hodgkinson, 66, was fatally shot by police who had been guarding Scalise, the House majority whip.

In San Francisco, a UPS employee opened fire inside a package delivery facility, killing three co-workers and himself, authorities said.