(NewsNation) — Under a new rule announced by the Biden administration Wednesday, migrants who don’t first seek protection in a country they passed through or haven’t applied online will be denied asylum.

The policy comes as tens of thousands amass along the southern border with the pandemic-era border policy known as Title 42 coming to an end Thursday. The administration’s new approach mirrors a Trump-era rule that required migrants to first seek and be denied asylum in another country before trying in the U.S.

The new policy will make it more difficult for those arriving at the border from Central and South America to qualify for asylum.

A federal judge struck down the previous Trump administration rule and the American Civil Liberties Union (ACLU) has issued a statement suggesting it will challenge the Biden plan in court.

“(Biden) has closed off the possibility of asylum in the United States to the majority of people seeking safety — in contradiction with our nation’s laws and values,” Jonathan Blazer, director of border strategies at the ACLU, said in a statement.

Under U.S. law, anyone who comes to the U.S. can ask for asylum. Over the past three years, Title 42 has allowed border officials to immediately expel migrants on public health grounds. Now that the policy is ending, an estimated 150,000 people are waiting along the U.S.-Mexico border.

The Biden administration says the border is not open and is urging migrants to apply for asylum online. The Department of Homeland Security (DHS) said 83,000 people have scheduled appointments at ports of entry over the past four months.

The administration has also sent 1,500 active-duty military personnel ahead of the expected surge to help border officials with administrative tasks.

On the other side of the border, the Mexican government has committed to accepting 30,000 people per month from Venezuela, Cuba, Haiti and Nicaragua who enter the U.S. illegally after Title 42 ends.

“Migrants who enter the United States unlawfully by crossing the Southwest Border, and not via a lawful pathway, will be returned to Mexico and may be transported away from Mexico’s northern border to locations in southern Mexico,” U.S. Customs and Border Protection Acting Commissioner Troy Miller said in a statement Thursday.

DHS will now return to Title 8 processing procedures, which still allows for expedited removals but typically gives those seeking asylum more time to make their case.

Removals under Title 8 also come with stiffer penalties than Title 42. Those who are removed under Title 8 are banned from entering the U.S. for five years and could face criminal prosecution for any subsequent attempt to cross the border illegally.

Since March 2020, Title 42 has been used to expel migrants at the U.S.-Mexico border nearly 2.8 million times. That’s about the same number of expulsions under Title 8 over the same time period.

Now, U.S. authorities are bracing for a surge in illegal crossings that could hit 13,000 a day.

Over the past three days, migrant apprehensions along the southern border have already skyrocketed to more than 30,000, according to DHS sources. The 10,000 daily apprehensions mark a 60% increase from the daily average in March, the most recent month of available data.=