United States officials are raising concerns about the potential danger posed by terror-backed sleeper cells within the nation, shortly after President Donald Trump’s successful directive to dismantle key nuclear sites in Iran.

Following Trump’s national address concerning U.S. military action on Iranian nuclear facilities, the Department of Homeland Security issued a new memo alerting the nation to an “elevated threat environment in the United States.”

The announcement from the National Terrorism Advisory System did not mention specific threats; however, it comes amidst Iranian officials’ warnings of possible retaliation.

“Law enforcement and security personnel are really focused now on trying to prevent anything from happening,” Balboni told Fox News Digital. “But the problem is if you’ve had tens of millions of people come across the border, you really don’t know where they are and what their capabilities are.” 

As tensions between the Middle East and the U.S. continue to spiral toward a breaking point, the National Terrorism Advisory System warns of U.S.-based individuals “plotting additional attacks” against pro-Israel targets, and U.S. government and military officials. 

“This is a time for calm, professionalism, information sharing and heightened awareness,” Balboni said. “This will not be the first time we face a challenge like this. But certainly because of the hostilities, there is a heightened fear, concern and awareness that these types of attacks could happen in the United States.”