Mike Brooks: Vigilance can deter terrorism
Mike Brooks: "[The Homeland Security Department] is telling you now to be vigilant, and viewers need to take heed of that warning."
Terror level threat is based on new intelligence.
The threat status is changed to 'high' amid fears of a plot against U.S. targets.
U.S. intelligence officials say they believe al Qaeda members are in Iran.
(CNN) -- The United States has raised the nation's terror threat level, saying the U.S. intelligence community believes al Qaeda has entered an "operational period worldwide" and might attack within the United States.
CNN law enforcement analyst Mike Brooks talked with CNN's Kyra Phillips about what that means in regard to national security.
PHILLIPS: How will additional levels of security [be put in place]?
BROOKS: We were at a yellow level. We just went to orange. We just came back down. Now we're going back up to orange again. So I think that [Homeland Security] is well-prepared. I spoke with the Metropolitan Police Department in Washington, which probably has more icons than any other city in the country and has done this and prepared for this in protection of its critical infrastructures for quite some time.
[The police] said that they are in a meeting with the chief right now to see if they're going to go up to level two of a three-tiered response, which basically means that they would just give special attention to many of the infrastructures and icons within the city, as well as opening up the joint operation center there in Washington.
Now one of the things that [Undersecretary of Homeland Security] Asa Hutchinson said that I think is important, I think needs to be driven home, speaking again as a former counterterrorism detective with the Metropolitan Police Department assigned to the FBI, is "Vigilance is a deterrent to terrorist activity."
Sometimes in the United States we get complacent. People need to understand that vigilance is important. Now they may say, "What is the going from yellow to orange to yellow to orange mean to me?" What it means to them is, when they go to a sporting event, when they are out in a shopping mall, when they're on their way to and from work or out walking the dog, if they see something that their gut tells them is not in place, that doesn't seem right to them, they should call the police. They should not feel that they are bothering the police, and police have told me all along that people should call the police whenever they feel something is out of place. They want to know about it. So let the police make the decision what to do.
So, again, I think a vigilant alert is the word of the day. We talk a lot about the United States since 9/11, and I think again we have been in full-disclosure mode, and that's the way the government has been. And I think many people are glad of that because many times they thought, well, the government never tells us anything. They're telling you now to be vigilant, and viewers need to take heed of that warning.