Homeland Security Secretary Kristi Noem on Tuesday said the department is reviewing interviews with some individuals who crossed the border under former President Joe Biden to identify potential threats following the conflict with Iran.

Senate Judiciary Chair Chuck Grassley, R-Iowa, questioned Noem during a DHS oversight hearing, asking about the "millions of people" who entered the U.S. under Biden’s "open border policy" and what steps Homeland Security has taken to protect against potential Iranian sleeper cells and related terrorism.

Noem replied that DHS works with intelligence agencies and law enforcement to investigate and find any threats on U.S. soil.

"Not only that, we go back and we are getting some of the individuals in some of the programs that we may have concerns about looking at social media, also going through those interviews that are necessary for some of our programs that the Biden administration abused and perverted under their time there as well," Noem said.

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"We know that we have many dangerous individuals that came in unvetted, and we are working every single day to find them and to make sure that we're preventing the next attack and preventing the next crime they may perpetuate against the American people," the secretary continued.

The comments come after the joint U.S.–Israel strikes on Iran on Saturday morning that officials say targeted Iranian leadership and key military installations.

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The conflict has led American counterterrorism agencies to quietly monitor suspected sleeper cells on U.S. soil, stepping up surveillance amid heightened fears of possible retaliation from Iran-linked operatives or sympathizers, Fox News Digital previously reported.

The sleeper cell concerns came into full focus over the weekend when authorities say a Senegalese man opened fire at patrons of an Austin, Texas, bar while wearing a sweatshirt that read "Property of Allah."

Fox News also learned Monday that a DHS memo was sent out over the weekend to various law enforcement agencies nationwide warning of potential cyberattacks and lone wolf physical attacks as a result of the U.S.-Israel bombing in Iran.

Fox News Digital’s Amanda Macias and Charles Creitz contributed to this report.

EXCLUSIVE: House Majority Leader Steve Scalise, R-La., is warning Democrats not to play politics with the Department of Homeland Security's (DHS) funding, particularly as the country is on high alert for any fallout from the U.S.-Israeli strikes on Iran.

"Put the safety and security of the American people first and stop playing political games to appease the far-left base, especially at a time like this," Scalise said in an interview with Fox News Digital.

The ongoing partial government shutdown centered on DHS, now in its 18th day, has taken on new significance in the wake of President Donald Trump's military action in Iran.

Bipartisan deals have funded 97% of the federal government through the end of the fiscal year on Sept. 30, but divisions between Democrats and Republicans over Trump's immigration crackdown have prevented any such compromise on DHS.

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House GOP leaders announced over the weekend that the chamber would vote this Thursday on a bipartisan DHS funding bill that passed in January in a bid to pressure Democrats to end the shutdown. 

That bill failed to advance in the Senate multiple times, with Democrats demanding new guardrails on immigration enforcement that Republicans have deemed nonstarters.

"We are on a higher level of alert, and this is not the time for Democrats to be playing games and shutting down the department that is focused on keeping Americans safe here at home," Scalise said. "So we're bringing this bill back up again to try to get them to come to their senses and open the Department of Homeland Security."

The bill passed in a 220-207 vote in late January, with just seven Democrats crossing the aisle in support. All but one House Republican, Rep. Thomas Massie, R-Ky., voted in favor.

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However, Scalise said "any responsible member of Congress" should vote for the legislation this time.

"The country is watching and expects members of Congress to take the safety of the American people at heart. And so I hope we get a much larger vote this time," he said.

DHS is a wide-ranging department that was created in the wake of the Sept. 11, 2001 terror attacks.

While it's most recently grabbed headlines for actions by Immigration and Customs Enforcement (ICE) and Customs and Border Protection (CBP), DHS is also responsible for a variety of national security-focused offices like the Cybersecurity and Infrastructure Security Agency (CISA) and the U.S. Secret Service.

Scalise pointed out that it's also critical to keeping the U.S. safe during global events being hosted within its borders.

"We had a hearing last week on the World Cup, the people in charge of security for the World Cup were saying that they may have to start canceling some events," he said. "And that was before Iran."