U.S. Border Patrol agents reportedly arrested an Afghan national on the FBI’s terrorism watchlist who illegally entered America by crossing its southern border with a group of migrants last week.

The individual, who was not identified, made it across the U.S.-Mexico divide near Otay Mesa, California, on Wednesday, Fox News national correspondent Bill Melugin tweeted on Sunday.

The reporter, who cited “multiple” U.S. Customs and Border Protection(CBP) sources, said he was told the FBI “confirmed the match” and the bureau is leading an investigation.

The Daily Wire has reached out to CBP as well as the FBI seeking comment.

News of the arrest generated a great deal of reactions on social media.

“And remember: got aways have never been higher. Vast stretches of border totally unguarded and unpatrolled as agents forced to process and release record influx,” said Stephen Miller, who served as a top aide to former President Donald Trump.

The reported arrest took place as the Biden administration made preparations for an expected influx of people at the border with the pandemic-era Title 42, which allowed authorities to quickly turn away migrants at the border on public health grounds, expiring at the end of Thursday. Multiple cities and at least one state declared emergencies as officials braced for a surge in migrants, many seeking entry through legal pathways.

Still, Republicans have assailed President Joe Biden for instituting “open border policies” that they say have fueled problems, such as fentanyl drug trafficking and illegal immigration. Some Democrats have also condemned the administration for its response to the border situation.

Homeland Security Secretary Alejandro Mayorkas on Sunday rejected the criticism. “It’s extraordinary what we’ve done over the past 18 months or so,” Mayorkas said during an appearance on CNN’s “State of the Union.” In addition, the secretary said Border Patrol encounters have dropped by half in the two days since Title 42 ended.

Melugin said Rep. Darrell Issa (R-CA), who represents a district along California’s southern border, confirmed the Afghan national arrest with a CBP contact.

“Biden’s open borders aren’t just a gateway to five million illegals, record human and child trafficking and the deadliest drug crisis in our history,” Issa said in a statement. “Biden’s reckless policy is also an open invitation to even the most wanted terrorists in the world to come to America.”