Department of Homeland Security Secretary Kristi Noem is sounding the alarm after President Donald Trump ordered strikes on Iranian nuclear facilities.

Asked by a reporter if she was concerned about threats in the United States from potential sleeper cells, she said that is something DHS is watching.

“When we talk about sleeper cells, a lot of the past, like in terms of hits on the president and other U.S. officials, those have been carried out—at least according to prosecutors—by individuals hired here, not sleeper cells. Is there a concern of something different?” the reporter said.

“We’ve seen some from overseas and some that have been here, maybe gone overseas for a short period of time, become radicalized and come back, or individuals that are right here in the United States. So we have to watch for all of it and be diligent on all of it, and we’ll continue to do so,” Noem responded.

“What do we know right now in regards to those sleeper cells? How is DHS tracking and following and seeking information?” the reporter pressed.

“I can’t necessarily share that with you, but I will tell you that we are continuing to evaluate every single thread and to proactively go after them before they do anything or take any activity,” the DHS secretary said.

“What I would tell the people that live in this country is to be grateful that they woke up this morning in the United States of America. We—because we woke up here—are more blessed than 99% of the people in the world because we live in a country where freedom and liberty is embraced. And that’s what our president was protecting by going after specific nuclear sites in Iran,” Noem said.

“That was something that was non-negotiable, and he did not do anything except take out the potential for that nuclear weapon to be utilized. This country is leading the world and has been for many years and will continue to do so as long as we still have strong leadership like President Trump’s in the White House. I believe that the president worked aggressively to make sure that we are safer, and we will be into the future as well,” she said.