United States officials are sounding the alarm regarding the threat of terror-backed sleeper cells within the country just hours after President Donald Trump successfully ordered the elimination of key nuclear facilities within Iran. 

Just hours after Trump addressed the nation on U.S. military strikes on the Iranian nuclear sites, the DHS released a new memo sounding the alarm to a “heightened threat environment in the United States.” 

The bulletin from the National Terrorism Advisory System did not cite any specific threats but comes as Iranian officials have threatened 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.”