CAMP PENDLETON ( — Several Southern California military bases were on heightened alert Monday after as many as 12 people were killed in a shooting at the Washington Navy Yard in the U.S. Capitol.

READ MORE: Clippers Barely Hold Off Celtics To Seal Victory, 114-111

Officials noted, however, that no additional security measures were put in place at bases including Camp Pendleton and Vandenberg Air Force Base. Experts say this indicates the East Coast shooting was likely an isolated incident.

John Haire, Chief of Public Affairs at Edwards AFB in Lancaster, told KNX 1070’s Margaret Carrero he did notice something different at the security gates this morning.

“It looks at your ID card and basically will tell this particular gate guard what your status is, and it will also say where you’re authorized, say when the card expires,” Haire said.

It was not immediately clear whether the measure was in response to the shooting in Washington.

READ MORE: Pasadena Prepares For Rose Parade Festivities Amidst Rising COVID-19 Cases

The 5,000-acre Naval Weapons Station in Seal Beach remained fully operational throughout the day and conducted business as usual as sailors and employees mourned the loss of the victims in Washington D.C.

The suspected gunman at the Navy Yard reportedly died in the incident at the Naval Sea Systems Command building, according to CBS News.

A law enforcement official told CBS News’ Pat Milton the suspected shooter apparently had a handgun, an AR-15 assault rifle, and a shotgun with him. He was wearing dark blue clothing.

Naval Sea Systems Command is the largest of the Navy’s five system commands and accounts for a quarter of the Navy’s entire budget.

It builds, buys and maintains the Navy’s ships and submarines and their combat systems.

MORE NEWS: WeHo Weed Industry Hoping To Be Cannabis Hotspot, Much Like Amsterdam, With Lounges, Cafes And Galleries

(TM and © Copyright 2013 CBS Local Media, a division of CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2011 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)