LAS VEGAS -- There are new concerns about the possibility of a terrorist attack in the U.S.

The FBI and the Department of Homeland Security have issued warnings to police agencies across the country after the arrest of a Colorado shuttle driver and others suspected in a potentially far-reaching terror plot.

The extra security was evident in places like New York City, where airports and train stations saw more police activity. That warning also extends to Las Vegas.

Local police said there have been no credible threats made on Las Vegas, but that doesn't mean the danger isn't here or that local families are in the clear.

“We cannot afford to think we would not be a desirable target. If you look at some of the worldwide terrorist bombings, those were hotels and tourist destinations," said Capt. Brett Primas, of Fusion Center.

That means Las Vegas could be a prime target for terrorists.

“It does concern me very much. It would concern me more if the airports close down,” Primas said.

Officials share their investigation efforts, warning other big cities that international criminals may be looking to do some damage.

Officers said people should keep an eye out for anything that could be used as an explosive device.

“That could be a backpack, a piece of luggage -- even a plastic water bottle that was going to be used on a airplane -- that's why we can't bring on more than three ounces of liquid," Primas said.

He said even shoes can contain a bomb.

Authorities also urged residents to watch for odd behavior. While they said they don't want residents walking around paranoid but mindful of other people and what they're doing.

“I don’t think there's been one terrorist attack that’s been carried out that there were not signs before it happened that someone failed to say something and act on it. That's what we don't want to happen here," Primas said.

Terrorism experts are continuously meeting with schools, casinos, businesses and people who are in charge of water systems and transportation to make sure everyone is on the same page.

Even after this arrest, authorities said the national threat level has not changed.