Updated

President Biden's acting director of U.S. Immigration and Customs Enforcement (ICE), Patrick Lechleitner, admitted that a terrorist was allowed to roam freely in the U.S. for nearly a year after crossing into the country illegally at the border.

At a briefing on Thursday, Lechleitner said the terrorist was arrested within 48 hours, only after ICE "became aware."

Lechleitner confirmed a report by The Daily Caller that federal authorities caught a terrorist illegally crossing into the U.S. via the southern border in March 2023. 

However, the terrorist was then released into the U.S. due to a "mismatch" after his name was run through the terror watch list, The Daily Caller reported.

DEMOCRATS DENY BORDER CRISIS, PLACE BLAME ON REPUBLICANS AND TRUMP

ICE acting director Patrick Lechleitner

U.S. Immigration and Customs Enforcement Deputy Director and Senior Official Performing the Duties of the Director Patrick Lechleitner speaks at a press conference in Washington, D.C., on Thursday. (Fox News)

The unnamed terrorist was a member of al-Shabab and was captured last month in Minneapolis, according to the outlet.

"A 27-year-old Somali native entered near San Ysidro, California, without inspection on March 13, 2023, and was arrested that same day by U.S. Border Patrol," ICE spokesperson Erin Bultje told Fox News. On Jan. 18, U.S. Immigration and Customs Enforcement (ICE) received information regarding the noncitizen’s threat to national security and took the noncitizen into ICE custody on Jan. 20, where he is currently detained in accordance with ICE policy, subject to the ongoing evaluation of their case."

SPEEDBOAT PULLS UP TO SAN DIEGO SHORE AND DROPS OFF GROUP OF SUSPECTED ILLEGAL MIGRANTS

When questioned by Jennie Taer of The Daily Caller about how many other terrorists have been apprehended in the interior after coming through the border, Lechleitner refused to answer her question.

The border in Texas

The U.S.-Mexico border in El Paso, Texas. (Kelly Laco/Fox News Digital)

CLICK TO GET THE FOX NEWS APP

Instead, he addressed the capture of the al-Shabab terrorist.

"I want to commend our personnel because as soon as we became aware of that — within 48 hours — he was apprehended, and he's currently in ICE custody," Lechleitner said. "I think that's an incredible result — a testament to how professional, quite honestly, how capable our personnel are."

According to the U.S. State Department, al-Shabab is al Qaeda's largest, wealthiest and most deadly affiliate. The group has murdered thousands of people in Somalia and the region, including Americans. 

Fox News' Bill Melugin contributed to this report.