(NewsNation) — Border agents are stopping individuals on the federal terror watchlist at a significantly higher rate than in previous years, and experts fear the ongoing immigration crisis could create a national security problem.

Agents along the southern border have stopped individuals on the government’s terror watchlist 38 times since October, according to data from U.S. Customs and Border Protection (CBP).

At the current pace, encounters involving individuals on the watchlist will surpass 150 by the end of this fiscal year. That’s well above the 98 stops made last year, and marks a notable increase since President Joe Biden took office.

From 2017 to 2020, border patrol agents recorded just 11 total encounters with individuals on the watchlist at ports of entry along the southern border.

“This is a significant threat to the United States,” said former U.S. Border Patrol chief Rodney Scott. “We’re ignoring the fact that there are real national security threats mixed in with this mass migration.”

The recent uptick in watchlist apprehensions coincides with a record-breaking number of migrants attempting to cross into the United States through Mexico.

In December, CBP agents encountered more than 250,000 migrants along the southern border — an all-time high for a single month. In December 2020, CBP encountered just over 40,000 migrants along the southern border.

The current data only takes into account migrants who have been caught, but authorities estimate tens of thousands of others have gotten away.

Despite the recent increase, encounters of individuals on the terror watchlist remain extremely rare. The 38 stops since October account for a tiny fraction (0.0060%) of all U.S. Border Patrol encounters.

Some of those stops may include multiple encounters with the same individual, CBP notes.

The terror watch list has an estimated 2 million names of people who represent a potential threat to the United States.

Meanwhile, the number of non-citizen gang members apprehended by border patrol increased to 751 last year — the highest total since CBP recorded nearly 1,000 gang-related stops in 2019.

So far in 2023, agents have apprehended 146 gang members, about a third of whom were affiliated with the international street gang MS-13.

Local officials believe more deterrence is the first step to slowing down the flow of illegal migrants.

“The lack of willigness of this administration to surge at the border, shut it down and deny illegal entry is something that needs to be addressed,” said Jonathan Lines, supervisor for District 2 in Yuma County, Arizona.

Recidivism rates among people attempting to cross the border has also risen in recent years.

More and more, agents stop migrants who’ve already been apprehended once before. In 2021, 27% of stops included someone who had already been encountered by CBP. In 2019 that rate was 7%.