Migrants from Honduras wait in a Border Patrol truck after turning themselves in upon crossing the U.S.-Mexico border Monday,…
FILE - Migrants from Honduras wait in a Border Patrol truck after turning themselves in upon crossing the U.S.-Mexico border. The U.S. government continues to report large numbers of migrants crossing the border, with an increase in adult crossers.

Nearly four months into the Biden administration, U.S. officials report only limited signs of progress in stabilizing a chaotic situation at the U.S.-Mexico border, with unauthorized migrant crossings continuing at multi-decade highs for this time of year.

The number of migrants encountered by U.S. authorities began rising last year and increased dramatically in early 2021.

U.S. Customs and Border Protection's enforcement data for April showed undocumented migration at a 20-year high. The agency reported 178,622 migrants apprehended for the month. Of those, 111,714 were expelled from the country under a pandemic-related emergency health order blocking most migrants from pursuing asylum claims or other forms of relief in the United States.

Border apprehensions in April were 3% higher than March's total of 173,348 and significantly higher than the February total of 101,120.

The data also suggest that increases in border encounters are leveling off and may have hit a plateau. But experts are unsure what's ahead and aren't ready to say the border crisis is easing.

"The kind of situation with CBP being overwhelmed by more vulnerable migrants may be starting to turn around," Migration Policy Institute analyst Jessica Bolter told VOA. "The one caution that I would give is that there have been instances historically where numbers have plateaued in April or gone down in April but then shot back up in May, so we'll really have to see the May numbers in order to know kind of where we stand."

FILE - Migrants pass the time at a migrant shelter, May 12, 2021, in McAllen, Texas.

The surge in migrant arrivals made the U.S.-Mexico border an early focus of President Joe Biden, who tapped Vice President Kamala Harris to oversee and coordinate the administration's response.

Speaking with VOA, White House immigration policy adviser Tyler Moran said border metrics do not tell the whole story.

"Migration is a normal phenomenon. The numbers go up and down for a number of different reasons," Moran said. "It could be push factors due to violence. It could be political instability. It could be natural disasters — also because our legal immigration system is so out of date."

Biden's Republican critics acknowledge the complexity of the situation while faulting the president's messaging that he would break from the restrictive immigration policies of former President Donald Trump.

"Although I believe that the current crisis has been unnecessarily caused or accelerated by misguided policies, I also understand that there are complex, interconnected sets of factors that play into the decision to leave one's country," Republican Representative Peter Meijer of Michigan said in a recent statement.

FILE - Three young migrants hold hands as they run in the rain at an intake area after turning themselves in upon crossing the U.S.-Mexico border, May 11, 2021, in Roma, Texas.

Single adults, unaccompanied minors

While much attention has been focused on border crossings by unaccompanied minors, some barely older than toddlers, the largest cohort of migrant arrivals comprises single adults.

In fact, according to CBP, the number of unaccompanied minors decreased slightly from March (18,960) to April (17,171), even as the total number of migrants continued to rise.

While most migrants continue to be expelled, the Biden administration has exempted unaccompanied minors and families with young children from the blanket deportation policy.

Processing, housing and caring for thousands of youths quickly became an urgent challenge for the new administration as Border Patrol stations unequipped to tend to children's needs became severely overcrowded.

As of early April, the U.S. had more than 5,700 unaccompanied minors in CBP facilities. In the weeks that followed, the government opened 14 emergency shelters run by the Department of Health and Human Services (HHS), the federal entity tasked with caring for migrant children. Subsequently, the number of minors in CBP custody dropped by more than 90%.

"The handling of unaccompanied children has improved, not just over the course of the several months but even in comparison to past administrations. I think that the Biden administration has tried to increase collaboration between different government agencies," Bolter said.

FILE - Children and adults wait in lines for donated food at a makeshift camp for migrants near the U.S.-Mexico border, May 14, 2021, in Reynosa, Mexico.

As of Tuesday, 675 children were in CBP custody and 19,387 were in the care of HHS. More than 444 others had been released to the care of parents or other guardians already living in the United States.

"We have been working to set up an orderly system to move those children as quickly as possible from Border Patrol into HHS custody, and then into the arms of their parents or sponsors," Moran told VOA.

Moran described HHS's emergency influx facilities as a short-term fix while longer-term capacities are expanded.

"We want to have enough state-licensed shelters in the states around the country so, when there is an increase of unaccompanied children in the future, that is the place that they go instead of these temporary facilities," she said.

Drug seizures

Migrant flows are not the only phenomenon of note at America's southern border. Federal authorities also monitor and interdict drug smuggling.

The latest data from CBP show drug seizures were up 6% in April from March 2021. Although cocaine and methamphetamine confiscation decreased, seizures of heroin nearly doubled, and fentanyl seizures increased by 34%. 
 
"So far in Fiscal Year 2021, fentanyl seizures have already surpassed those from all of Fiscal Year 2020, with 6,494 through April 2021 compared to 4,776 for all of Fiscal Year 2020," CBP reported in a press release earlier this month.

Increased drug flows were discussed at a recent congressional hearing, with Republican Senator Rick Scott of Florida asserting that drug cartels are benefiting as federal "resources are being diverted to manage the humanitarian crisis at the southern border."

U.S. Homeland Security Secretary Alejandro Mayorkas responded that historically, most illegal drugs enter the United States not between ports of entry but "hidden in compartments of vehicles" entering the United States at official border checkpoints.

Jorge Agobian contributed to this report.