WASHINGTON — President Joe Biden on Tuesday unveiled plans to enact immediate significant restrictions on migrants seeking asylum at the U.S.-Mexico border as the White House tries to neutralize immigration as a political liability ahead of the November elections.

The long-anticipated presidential proclamation would bar migrants from being granted asylum when U.S. officials deem that the southern border is overwhelmed. The Democratic president had contemplated unilateral action for months after the collapse of a bipartisan border security deal in Congress that most Republican lawmakers rejected at the behest of former President Donald Trump, the presumptive GOP presidential nominee.

Biden said he preferred more lasting action via legislation but “Republicans have left me no choice.” Instead, he said he was acting on his own to “gain control of the border” while also insisting that “I believe immigration has always been the lifeblood of America.”

Trump “told the Republicans ... that he didn't want to fix the issue, he wanted to use it to attack me,” Biden said. “It was a cynical, extremely cynical, political move and a complete disservice to the American people who are looking for us not to weaponize the border but to fix it.”

Trump, on the other hand, used his social media account to assail Biden again over immigration, saying the Democrat had “totally surrendered our Southern Border” and his order was “all for show” ahead of their June 27 presidential debate.

The order will go into effect when the number of border encounters between ports of entry hits 2,500 per day, according to senior administration officials. That means Biden's order should go into effect immediately, because the daily averages are higher now. Average daily arrests for illegal crossings from Mexico were last below 2,500 in January 2021, the month Biden took office. The last time the border encounters dipped to 1,500 a day was in July 2020, at the height of the COVID-19 pandemic.

The restrictions would be in effect until two weeks after the daily encounter numbers are at or below 1,500 per day between ports of entry, under a seven-day average. Those figures were first reported by The Associated Press on Monday.

Homeland Security said increased enforcement with Mexico since high-level bilateral meetings in late December has lowered illegal crossings but is “likely to be less effective over time,” creating a need for more action. “Smuggling networks are adaptable, responding to changes put in place,” the department said in a federal rule published Tuesday.

The department predicts that arrests for illegal crossings may climb to a daily average as high as 6,700 from July through September.

Once this order is in effect, migrants who arrive at the border but do not express fear of returning to their home countries will be subject to immediate removal from the United States, within a matter of days or even hours. Those migrants could face punishments that could include a five-year bar from reentering the U.S. or even criminal prosecution.

Meanwhile, anyone who expresses that fear or an intention to seek asylum will be screened by a U.S. asylum officer but at a higher standard than currently used. If they pass the screening, they can pursue more limited forms of humanitarian protection, including the U.N. Convention Against Torture.

“We're troubled to see this administration raise the bar on asylum seekers who are coming to our southern border and exercising a legal right,” said Krish O'Mara Vignarajah, president and CEO of Global Refuge. “Certainly no one wants to see migrants who may be coming to seek a better life or for economic opportunity game the asylum system, but we see in our clients and in other immigrants people who are fleeing the most dire of circumstances at a time of unprecedented global migration and believe that the U.S. is still a beacon of hope and refuge.”

At the border Tuesday, there were no visible signs of immediate impact.

Iselande Peralta, a Haitian mother staying at a migrant shelter in Reynosa, Mexico, with her 3-year-old son, said the U.S. was within its rights to enforce new restrictions. She has been trying for 10 months to get an appointment through U.S. Customs and Border Protection's online app, called CBP One. Peralta, 26, wouldn't consider crossing illegally and considers CBP One her best option.

“Even if I was crazy, I wouldn't cross the river. How would I do that with a child as young as him? I'm willing to wait,” she said.

Biden's directive is coming when the number of migrants encountered at the border have been on a consistent decline since December, but senior administration officials say the numbers are still too high and could spike in better weather, as is typical.

Yet many questions and complications remain about how Biden's directive would be implemented.

For instance, the administration already has an agreement with Mexico in which Mexico agrees to accept up to 30,000 citizens a month from Cuba, Haiti, Nicaragua and Venezuela once they are denied entry from the U.S., and senior administration officials say that will continue under this order. But it is unclear what happens to nationals of other countries who are denied under Biden's directive.

Four senior administration officials, who insisted on anonymity to describe the effort to reporters, acknowledged that Biden's goal of deporting migrants quickly is complicated by insufficient funding from Congress to do so. The administration also faces certain legal constraints when it comes to detaining migrant families, and the administration said it would continue to abide by those obligations.

The legal authority being invoked by Biden comes under Section 212(f) of the Immigration and Nationality Act, which allows a president to limit entries for certain migrants if their entry is deemed “detrimental” to the national interest. Senior officials expressed confidence that they would be able to implement Biden's order, despite threats from prominent legal groups to file lawsuits over the directive.

“We intend to sue,” Lee Gelernt, an attorney for the American Civil Liberties Union who successfully argued similar legal challenges when Trump was president. “A ban on asylum is illegal, just as it was when Trump unsuccessfully tried it.”

The senior administration officials insisted that Biden's proposal differs dramatically from that of Trump, who leaned on the same provisions of the Immigration and Nationality Act that Biden is using, including Trump's 2017 directive to bar citizens of Muslim-majority nations and his efforts in 2018 to clamp down on asylum.

Biden's order outlines several groups of migrants who would be exempted due to humanitarian reasons, including victims of human trafficking, unaccompanied minors and those with severe medical emergencies.

The directive would also exempt migrants who make appointments with border officials at ports of entry using the CBP One app. About 1,450 appointments are made a day using the app, which launched last year to allow migrants to make asylum claims.

Immigration advocates worry that Biden's plan would only increase an already monthslong backlog of migrants waiting for an appointment through the app, especially when immigration authorities do not have an accompanying surge of funding.

It could also be difficult for border officials to quickly remove migrants when many agents are already tasked with helping in shelters and other humanitarian tasks, said Jennie Murray, the president of the National Immigration Forum.

“Customs and Border Protection cannot keep up with apprehensions as it is right now because they don't have enough personnel so it would cause more disorder,” she said.

Republicans dismissed Biden's order as nothing more than a “political stunt” meant to show toughened immigration enforcement ahead of the election.

“He tried to convince us all for all this time that there was no way he could possibly fix the mess,” GOP House Speaker Mike Johnson said at a news conference. “Remember that he engineered it.”

In a call organized by Trump's campaign, Stephen Miller, a senior adviser in Trump's White House who orchestrated his most polarizing immigration policies, and Tom Homan, former acting director of the Immigration and Customs Enforcement in the Trump administration, said Biden's order essentially would allow 2,500 people into the country a day and legalize the illegal entry into the U.S.

“The only reason they're doing this is because of the election,” Homan said. “They've had three and a half years to take action and done nothing.”

Democratic Senate Majority Leader Chuck Schumer said legislation would have been more effective, but “Republican intransigence has forced the president's hand.”