Washington — The number of unauthorized entries along the southern border has dropped to an average of 4,400 per day after soaring to 10,000 last week ahead of the expiration of Title 42 border restrictions, a senior U.S. official said Wednesday, attributing the sharp drop to increased deportations, tighter asylum rules and efforts by other countries to stop U.S.-bound migrants.

Over the past two days, U.S. Border Patrol agents have recorded fewer than 4,000 migrant apprehensions, a 60% decrease from the record daily border crossings seen before May 11 when the Title 42 pandemic-related restrictions on migration expired, said Blas Nuñez Neto, the Department of Homeland Security's top immigration policy official.

The end of Title 42, which allowed U.S. border agents to expel migrants on public health grounds, was expected to trigger a spike in migration. While illegal border crossings did soar just before Title 42 ended, they plummeted soon after, Nuñez Neto said.

"We attribute the reduction in encounters at our border both to the consequences that we have strengthened and put in place for unlawful entry, and the lawful pathways that we have expanded, but also to the actions of our foreign partners," Nuñez Neto told reporters during a briefing Wednesday.

Nuñez Neto noted the Mexican and Guatemalan governments had dispatched law enforcement and military units to their southern borders to slow U.S.-bound migration. In Panama's Darién Gap, he added, Panamanian and Colombian authorities were cracking down on the smuggling of migrants across the roadless and mountainous jungle. In recent days, Nuñez Neto said, migrant entries along the Darién have declined.

While Title 42 allowed the U.S. to cite the COVID-19 pandemic to summarily expel hundreds of thousands of migrants without hearing their asylum claims, the policy also fueled a spike in repeat border crossings among those expelled to Mexico, since they did not face the consequences deportees typically face under immigration law.

Since the end of Title 42, the Biden administration has increased regular deportations and returns to migrants' home countries and Mexico, which recently agreed to accept Cubans, Haitians, Nicaraguans and Venezuelans turned back by the U.S. Unlike Title 42, formal deportations ban deportees from reentering the U.S. for at least five years and make them subject to criminal prosecution if they attempt to enter the country again.

More than 1,000 Cubans, Nicaraguans and Venezuelans have been returned to Mexico since Title 42 was lifted, Nuñez Neto. Thousands of additional migrants have been placed on deportation flights to their home countries, including Colombia, Ecuador,  El Salvador, Guatemala, Honduras and Peru, he added.

Nuñez Neto said U.S. border officials have recorded a 98% drop in the number of Venezuelan migrants crossing the southern border illegally in recent days. Arrivals from crisis-stricken Venezuela increased sharply in the lead-up to Title 42 expiring.

Along with increasing deportations, the Biden administration has also tightened asylum eligibility rules. A rule implemented last week disqualifies migrants from asylum if they cross the southern border unlawfully after failing to request refuge in a third country, like Mexico or Guatemala, on their journey north.

While the Biden administration has increased enforcement, including through an asylum restriction that resembles a Trump administration regulation, to reduce the historically high levels of border arrivals recorded over the past two years, it has also expanded legal avenues would-be migrants can use to enter the U.S.

A phone app is allowing roughly 1,000 migrants in Mexico to secure appointments to enter the U.S. at border ports of entry each day, so they can be processed in an orderly fashion and allowed to seek asylum inside the country. Nuñez Neto said more than 5,000 asylum-seekers had been processed under the system since Friday.

Up to 30,000 citizens of Cuba, Haiti, Nicaragua and Venezuela are also being allowed to fly to the U.S. on a monthly basis if Americans file sponsorship requests on their behalf. Migrants from these countries who cross the southern border illegally are being offered the option to voluntarily return to Mexico so they can apply for this program, instead of facing deportation under the tighter asylum rules, according to an internal government memo obtained by CBS News.

Pillars of the Biden administration's border strategy, however, are in legal peril.

Republican-led states are asking a federal judge in Texas to block the sponsorship program for Cuban, Haitians, Nicaraguans and Venezuelans, arguing the administration does not have the authority to admit 30,000 migrants each month outside the visa system. At the same time, the American Civil Liberties Union recently asked a federal judge in California to declare the new asylum restriction illegal, saying it places refugees in harm's way.

Editor's note: A previous version of this story included an incorrect figure for the number of average daily crossings since the end of Title 42.

Camilo Montoya-Galvez

Camilo Montoya-Galvez is the immigration reporter at CBS News. Based in Washington, he covers immigration policy and politics.

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