WASHINGTON — Facing mounting political pressure over the migrant influx at the U.S. southern border, President Joe Biden on Tuesday signed an executive order that will temporarily shut down asylum requests once the average number of daily encounters tops 2,500 between official ports of entry, according to a senior administration official.

The shutdown would go into effect immediately since that threshold has already been met, a senior administration official said. The border would reopen only once that number falls to 1,500. The president’s order would come under the Immigration and Nationality Act sections 212(f) and 215(a) suspending entry of noncitizens who cross the southern border into the United States unlawfully. 

Senior administration officials said Tuesday in a call with reporters that “individuals who cross the southern border unlawfully or without authorization will generally be ineligible for asylum, absent exceptionally compelling circumstances, unless they are accepted by the proclamation.”

The officials said that migrants who don’t meet the requirement of having a “credible fear” when they apply for asylum will be immediately removable, and they “anticipate that we will be removing those individuals in a matter of days, if not hours,”

The White House conveyed details of the long-awaited move to lawmakers on Monday, but confirmed details of the executive order Tuesday morning ahead of planned remarks by the president in the East Room of the White House alongside mayors from several border towns.

“It’s definitely a step in the right direction,” said Texas state Rep. Eddie Jones, Jr., whose district includes Eagle Pass, Texas. “One of a number of steps that are necessary for us to be able to secure the border.”

In 2018, the Trump administration tried to enact similar border restrictions but courts blocked them. The Biden administration now expects to defend the executive order against legal challenges.

The executive order will also have some exceptions, including for unaccompanied children. 

In a written statement, Donald Trump campaign spokesperson Karoline Leavett claimed that exception would give a “green light to child traffickers and sex traffickers” while reiterating the former president’s rallying cry that “the border invasion and migrant crime will not stop until Crooked Joe Biden is deported from the White House.”

Republican lawmakers are slamming the move as too little, too late. 

“(Biden) created a crisis at the border intentionally,” said Sen. Kevin Cramer . R-ND. “(The executive action) has more political risk than political benefit, particularly because his own base is going to reject it.”

But the White House has repeatedly argued that it was congressional Republicans who have failed to act on immigration. Earlier this year, Trump urged House GOP members to kill a bipartisan border funding bill that had been negotiated in the Senate. At the time, House Speaker Mike Johnson and other  Republicans said that the Senate bill didn’t go far enough and they argued that a more hardline immigration bill in the House was preferable. 

“President Biden has led a historic opening of lawful pathways for individuals to and including families, to enter the United States through a lawful process, including the CBP One mobile application to request an appointment to present at a port of entry, as well as family reunification programs in countries throughout the region and a historic parole process for Cubans, Haitians, Nicaraguans and Venezuelans,” a senior administration official said. “And so this measure that we are announcing today comes alongside those lawful pathways,”

The executive action comes on the heels of a historic presidential election in Mexico and just as the campaign in the U.S. ramps up. Trump has a 30-point edge with registered voters on the question of which candidate would handle immigration and border security better, including a 23-point edge among Latino voters, according to a late-March CNBC national poll.

Many immigrant advocates are furious at the president’s harsher immigration policies and argue the changes will cause chaos.

“It is a betrayal of what we were told in his campaign four years ago,” said Lindsay Toczylowski, the executive director for the California-based Immigrant Defenders Law Center. “We were told that President Biden would be restoring humanity at our border…But what we are seeing is that history is repeating itself.”