▶ Watch Video: Border apprehensions top 100,000 in February as U.S. struggles to house migrant children The number of families and unaccompanied children taken into U.S. custody along the southern border continued to increase in February, creating a major logistical test for the Biden administration during its first month in office, according to government data released Wednesday. U.S. Customs and Border Protection (CBP) carried out more than 100,000 apprehensions in February, a 28% increase from the previous month. More than 71,000 single migrant adults were taken into custody, the vast majority of whom were expelled under a public health authority first invoked by the Trump administration. However, nearly 60% of the more than 19,000 migrant parents and children apprehended in February were processed under U.S. immigration law, with many allowed to seek asylum or other forms of protection while in American communities. The number of apprehensions of migrant families last month increased by 163% over January’s total, and was the highest since September 2019. U.S. border agents also took into custody nearly 9,500 unaccompanied children. The Biden administration has shielded unaccompanied minors from the Trump-era border expulsions, which were authorized by the Centers for Disease Control and Prevention (CDC) in March 2020. “We continue to struggle with the number of individuals in our custody, especially given the pandemic,” Troy Miller, the acting CBP commissioner, said on a call with reporters Wednesday. The marked rise in unaccompanied children entering U.S. border custody — a 21-month high — has become a significant challenge for the Biden administration. U.S. law requires border agents to transfer most unaccompanied minors to the Office of Refugee Resettlement within 72 hours, but the agency has been scrambling to find bed space for the children, which was limited to enforce social distancing. The refugee office is currently evaluating whether it can use Moffett Federal Airfield, a National Aeronautics and Space Administration installation in northern California, as an “influx” facility to house unaccompanied migrant children, NASA spokesman Darryl Waller told CBS News. The refugee agency has already reopened a Trump-era influx facility in Carrizo Springs, Texas, to house hundreds of migrant teens. CBP noted that approximately 25,000 of the migrants taken into custody in February had been encountered more than once, highlighting that some migrants cross the border again after being expelled. “We are seeing higher than usual recidivism rates as a result of COVID protocols,” a CBP official who requested anonymity said. “So the number of encounters, while they impact our operations at Border Patrol, they also can continue to overstate the migrant flows that we are seeing.” Last month, the refugee agency, which is a division of the Department of Health and Human Services (HHS), received more than 7,000 unaccompanied children — a record high for the month of February. The agency is currently holding more than 8,100 of these minors, who are supposed to be released to vetted sponsors, typically relatives living in the U.S. The upward trend of unaccompanied children has not ceased in March. During the first nine days of the month, more than 3,500 unaccompanied minors entered U.S. custody, according to preliminary government data reviewed by CBS News. The increasing number of arrivals and the limited bed space at U.S. shelters has created a massive logjam of unaccompanied minors stuck in Border Patrol holding facilities, most of which are police-like stations unfit to house children. As of Monday, there were more than 3,200 unaccompanied children in Border Patrol custody and nearly 1,400 of them had been held past the three-day legal limit, according to internal CBP documents obtained by CBS News. During the call with reporters, Miller, the CBP chief, said he could not provide an updated figure of unaccompanied children in the agency’s custody, saying the numbers constantly fluctuate and are law-enforcement sensitive. “We’re doing everything that is possible to move the children out of our custody as quickly as we should, in a safe and healthy manner,” he said. Miller also confirmed that some HHS officials are “integrated” within CBP facilities to expedite the release of unaccompanied children to sponsors. He added that minors in custody have access to medical contractors, welfare checks, blankets, hot meals and showers at least every 48 hours. “Most of us are parents, fathers, mothers. I myself have a 6-year-old,” Miller said. “These Border Patrol agents go above and beyond every single day to take care of the children.” Biden administration says “border is not open… 07:02 Republicans have accused the Biden administration of fueling the recent increase in border apprehensions, denouncing its immigration practices as “open border” policies. Roberta Jacobson, President Biden’s top adviser on U.S.-Mexico border policy, said the marked increase in people entering U.S. custody may be partly driven by a sense of “hope” among migrants. “There was a significant hope for a more humane policy,” Jacobson said during the White House press briefing on Wednesday, noting that restrictive Trump-era policies created “pent-up demand” among migrants and asylum-seekers. Jacobson also blamed misleading appeals by smugglers, as well as conditions in Central America, including poverty and violence. She noted the region is still recovering from two devastating hurricanes last fall. The Biden administration has said it will focus on addressing the root causes of migration through investment in Central America and the expansion of legal avenues for people to come to the U.S. On Wednesday, the State Department announced it had reinstated an Obama-era program ended by the Trump administration that allows certain Central American children to reunite with family members in the U.S. Miller noted that single adults and families continue to be rapidly expelled to Mexico or their home countries under the CDC edict. “Let’s be clear: the border is not open,” he said. Nicole Sganga contributed to this report.