SAN DIEGO (CBS 8) - Concerns over ISIS have the U.S. Military taking action and increasing the terror threat at U.S. Bases.

Security conditions are now at the highest level the nation has seen in the past four years.

The threat level Bravo is defined as a measure taken when there is an increase and predictable threat of terrorism.

Friday's announcement marks the fifth time the United States Military has reached Bravo status.

It happened twice in 2003, regarding concerns over Al-Qaeda, and again in May of 2011, following the death of Osama Bin Laden.

The last time was on the tenth anniversary of the September 11th attacks.

Gary Wilson is a retired Marine Corps Colonel, and he was stationed at Camp Pendleton when the treat level reached its highest; Delta. That was on 9/11.

In this case, he said it is not as dire as people may think, but there is still reason to be concerned.

"i think its part of normal course of action, but it's a great reminder for the public to be more aware. There is nothing eminent. It's more of a pre-cautionary measure," he said.

Colonel Wilson said changing the threat level is a good idea and can often keep adversaries off guard.

The terrorist group ISIS is the reason behind the most recent threat level change.

CBS News reported federal agencies had been sending out bulletins to law enforcement agencies all over the country saying homegrown extremists may elude attention and attack with little or no warning.

Colonel Wilson said it is critical for those agencies to share information given how much has changed over the years.

He hopes the Bravo level will encourage them to do just that.

According to CBS News, the director of the FBI held a conference call on Friday with representatives from 500 different police departments encouraging them to share information with each other.