▶ Watch Video: Migrant apprehensions at U.S. border hit 21-year high

Brownsville, Texas — Homeland Security Secretary Alejandro Mayorkas on Thursday strongly defended the Biden administration’s strategy for dealing with migration to the U.S.-Mexico border, where inderdictions of migrants and asylum-seekers have reached levels not seen in over two decades.

Standing in front of Border Patrol vehicles in south Texas, Mayorkas said the administration is expanding enforcement efforts to deter economic migrants from attempting to enter the U.S. without permission, while gradually expanding access to the U.S. asylum system for those fleeing violence.

“It is critical that intending migrants understand clearly that they will be turned back if they enter the United States illegally and do not have a basis for relief under our laws,” Mayorkas told reporters, acknowledging that the “unprecedented number” of border crossings poses a “serious challenge.” 

U.S. Customs and Border Protection (CBP) carried out 212,000 migrant apprehensions in July, a 21-year high, according to data released Thursday. More than 110,000 single adult migrants were taken into custody, the majority of whom were expelled to Mexico under a public health authority first invoked under the Trump administration.

However, nearly 88% of the more than 83,000 migrant parents and children taken into custody as families in July were processed under U.S. immigration law and allowed to seek asylum. U.S. border officials also encountered an all-time high 19,000 unaccompanied children, whom the Biden administration has categorically shielded from the expulsion policy, known as Title 42.

“It is a big number,” Raul Ortiz, the incoming chief of U.S. Border Patrol, told CBS News during an interview Tuesday. “I have a huge flow of migrants coming across here in south Texas. I have the same thing two or three hundred miles up the river in Del Rio, Texas. And then I have the same thing occurring in Yuma, Arizona. It really has forced us to rethink how we do business.”

Mayorkas attributed the rise in migration to violence, poverty and corruption in Central America, problems that he said the Biden administration is seeking to mitigate through foreign aid.

“Young boys whose lives are threatened if they decline to join a gang,” Mayorkas said, providing examples of would-be migrants. “Young women who are vulnerable to rape while they walk to school.”

Secretary of Homeland Security Alejandro Mayorkas attends a news conference along with incoming Border Patrol Chief Raul Ortiz, in Brownsville, Texas, on August 12, 2021.

Nicole Sganga / CBS News

But Mayorkas said the spike in border apprehensions was also fueled by the resurgent U.S. economy and the Biden administration’s reversal of several Trump-era policies, such as the practice of requiring asylum applicants to wait in Mexico, often in dangerous and squalid conditions, for their U.S. court hearings.

“Another reason is the end of the cruel policies of the past administration and the restoration of the rule of laws of this country that Congress has passed, including our asylum laws that provide humanitarian relief,” Mayorkas said.

In response to the surge in migrant encounters and concerns about the spread of the Delta variant of the coronavirus across U.S. communities, the Biden administration has been ramping up deportations and prosecutions of border-crossers, including families traveling with children.

“Now, of course, the Delta variant makes the situation more difficult. Our capacity to test, isolate and quarantine the vulnerable population — those that make legal claims for asylum — is stretched,” Mayorkas said, adding that DHS is “building new capacity” to mitigate health risks to migrants and neighboring communities along the Southwest border. 

The secretary acknowledged an “increase in the positivity rate among the migrant population” in recent weeks, but pointed out that the positivity rate among the migrant community is equal to or lower than that of border communities. 

Since last month, some Central American families have been subjected to a fast-track deportation policy known as “expedited removal,” which allows U.S. border agents to repatriate migrants without allowing them to appear before an immigration judge. 

Last week, U.S. authorities also started flying Central American migrants to southern Mexico under the Title 42 public health edict, which bars them from applying for asylum. Ortiz said “hundreds” of border-crossers have been placed on these expulsion flights so far, including 250 migrants who departed south Texas on Tuesday. 

Mayorkas said the expulsion flights are designed to curb repeat border crossing attempts, which he noted made up 27% of the migrant apprehensions in July.

“[We are] certainly taking an opportunity to leverage Title 42 to fly people back into Mexico. We repatriate people across the port of entry, but certainly have an ability to transport them even further south, closer to their home country,” Ortiz said. “I think it is a benefit for them as well as a benefit for us, because then we don’t have the overcrowding that exists at some of our facilities and [it] allowed us to ease some of that pressure.”

The expulsion flights and the fast-track deportation program for families have alarmed advocates for asylum-seekers, including the United Nations refugee agency, which said the practice of flying Central Americans to southern Mexico could strain the “humanitarian response capacity” in the region.

“These expulsion flights of non-Mexicans to the deep interior of Mexico constitute a troubling new dimension in enforcement of the COVID-related public health order known as Title 42,” the refugee agency said in a statement Wednesday.

Kennji Kizuka, a researcher at Human Rights First, traveled to the Mexican border cities of Nuevo Laredo and Reynosa this week to interview asylum-seekers affected by U.S. policy. He said he spoke with migrants from Central America, Cuba, Haiti and other countries who expressed fear of being victimized in these Mexican cities, which are located in a state the U.S. government warns Americans not to visit because of rampant crime, including kidnappings.

“People are really confused and worried that there’s not going to be any opportunity to request asylum at ports of entry,” Kizuka told CBS News. “People are really scared. They are scared to even go outside and buy food at a local supermarket.”

Kizuka’s group has compiled a list of more than 3,200 reports of kidnappings, rapes and assaults against migrants stranded in Mexico as a result of the Title 42 rule since January. 

While the Centers for Disease Control and Prevention (CDC) extended the Title 42 expulsions indefinitely earlier this month, Biden administration officials have acknowledged that they will not always have that emergency authority at their disposal. 

After holding talks with the Biden administration for six months, the American Civil Liberties Union last week revived its lawsuit against the Title 42 expulsions. U.S. District Judge Emmet Sullivan, who has previously ruled that Title 42 does not authorize expulsions or override U.S. immigration law, could issue a decision soon that could block the expulsions of families with children. 

“We certainly are concerned that at some point Title 42 may not be an opportunity for us to repatriate migrants back to Mexico or into their home country,” Ortiz said. “So we always have to plan in case of an emergency situation or something else changes.” 

Mireya Villarreal contributed to this report.