ICE sounds alarm on what migrants are failing to bring to border as fears mount after ISIS arrests

The head of Immigration and Customs Enforcement (ICE) is warning that it is "quite common" for illegal immigrants to arrive at the southern border with no information about them on record after authorities nabbed eight Tajikistan nationals with ties to ISIS who allegedly crossed the southern border.

Acting ICE Director Patrick Lechleitner was asked by NewsNation in an interview about the bust of the eight foreign nationals.

All eight Tajikistan nationals allegedly crossed the U.S. southern border illegally, and, according to a federal source familiar with the sting, no information was initially flagged with U.S. Customs and Border Protection (CBP) or with the U.S. Department of Homeland Security (DHS) during processing.

AUTHORITIES NAB 8 SUSPECTED TERRORISTS WITH TIES TO ISIS IN MULTI-CITY STING OPERATION

The suspected terrorists were "fully vetted" and nothing was flagged, according to Fox News' federal source. The source said after the suspected terrorists were released into the U.S., information was flagged with national security concerns, including the individuals' ties to ISIS.

Lechleiter said in the interview with NewsNation that "sometimes there is just no information on individuals" when they’re being vetted by Border Patrol.

"It is quite common where there is just nothing, you don't have anything. There's no criminal convictions, no threat information or whatever on these individuals. Or maybe these individuals are from an area that is particularly of concern but that pops up later when you get information later on," he said. 

CHINESE, JORDANIAN, TURKISH ILLEGAL IMMIGRANTS CAUGHT IN LARGE NUMBERS AT SOUTHERN BORDER

"And as soon as we become aware of any information, like in this case we became aware, working collaboratively with FBI, we went out and got them."

DHS and the FBI issued a joint statement about the matter earlier this week.

"Over the last few days, ICE agents arrested several non-citizens pursuant to immigration authorities," the statement said. "The actions were carried out in close coordination with the FBI’s Joint Terrorism Task Forces. The individuals arrested are detained in ICE custody pending removal proceedings.  

"As the FBI and DHS have recently described in public and partner bulletins, the U.S. has been in a heightened threat environment. The FBI and DHS will continue working around the clock with our partners to identify, investigate and disrupt potential threats to national security," 

CLICK HERE FOR MORE COVERAGE OF THE BORDER SECURITY CRISIS

Lechleitner’s comments are the latest warning from top officials about the risks of a potential breach at the border. Earlier this year, FBI Director Christopher Wray warned of a "wide array of very dangerous threats that emanate from the border."

"I want to be a little bit careful about how far I can go in an open session," Wray told Senate lawmakers in March. "But there is a particular network where some of the overseas facilitators of the smuggling network have ISIS ties that we’re very concerned about and that we’ve been spending an enormous amount of effort with our partners to investigate. Exactly what that network is up to is something that is, again, the subject of our current investigation."

Former ICE chief of staff Jon Feere told Fox News Digital it is difficult to vet people coming into the U.S., even if they enter legally on a visa, and particularly if they enter illegally.

"When a random person shows up at our border with no paperwork, no known background, our first instinct can't be to simply allow them to enter the United States. And we're going to have to make the tough decision to say no in many instances," Feere said. 

"Now, the odds of a bad person coming through are low when we're talking small numbers. But when we're dealing with mass illegal immigration, as we're experiencing now, the odds of a bad actor coming through increase, and the threats that this administration has created will be felt for years to come."

Feere, now at the Center for Immigration Studies, also faulted other agencies for admitting people into the U.S. and then expecting ICE to deal with the outcome.

"There's this expectation that, 'Well, we'll just let them in and hope that ICE cleans up any problems.' And then when something bad does happen and ICE doesn't locate them in time, it seems the finger-pointing is all too often at ICE," he said. 

Fox News' Stepheny Price and Bill Melugin contributed to this report.