Migrant children who had crossed the US-Mexico border alone began to trickle into a convention center in Dallas late Wednesday, as the administration races to alleviate overcrowded border facilities. The federal government has more than 14,000 migrant children in its custody, administration officials said Thursday, even as they insist that what is happening on the southern border does not constitute a crisis. The growing number of unaccompanied children at the border has overwhelmed resources, which had already been strained as a result of the coronavirus pandemic, spurring officials to seek out facilities to accommodate children, including the Kay Bailey Hutchison Convention Center in Dallas. The center – one of the largest in the country and located in downtown Dallas – has been transformed into an emergency intake site for more than 2,000 children. The Department of Health and Human Services confirmed that 200 children had arrived Wednesday. Early Thursday morning, dozens of people wearing American Red Cross vests also trickled into the building. “In response to a recent surge of young people arriving at the U.S.-Mexico border without parents or guardians, the American Red Cross has been asked to temporarily support (the Federal Emergency Management Agency) and the Office of Refugee Resettlement (ORR) to ensure these unaccompanied children have a safe place to stay,” the American Red Cross said in a statement. Migrant children transferred to the center will be provided games and books, according to a memo sent to local organizations by Catholic Charities Dallas, which is involved in the effort. The memo, obtained by CNN, says the goal is to have most of them at the center for no more than five days. FEMA sent 3,000 cots, 6,000 blankets and 36,000 liters of water to the center, according to an agency official. The site has been outfitted to include sleeping quarters, meals, toiletries, laundry and access to medical services, HHS said in a statement. “This approach will help decrease overcrowding at (Customs and Border Protection) facilities and ensure children are moved into ORR shelters, where children receive educational, medical, mental health, and recreational services until they can be unified with families or sponsors without undue delay,” the department said in a statement. Thousands of children have crossed the US-Mexico border alone in recent months, leaving many border facilities over capacity. Administration officials said Thursday that there were more than 9,500 children in HHS custody and roughly 4,500 with Customs and Border Protection. That represents an increase from earlier this week. More than 500 unaccompanied migrant children have been in US Border Patrol custody for more than 10 days, CNN has learned, marking yet another jump in the number of children staying in custody longer than US law permits. The average time in custody for unaccompanied children has increased to more than 130 hours, exceeding the 72-hour limit. The administration officials said Thursday that most adult migrants and migrant families were being expelled. But they acknowledged there were limitations on Mexico’s ability to take in migrants, particularly those with young children. And they repeated that the Biden administration would not expel unaccompanied minors. Homeland Security Secretary Alejandro Mayorkas said Thursday that the border facility he had recently visited was “crowded.” “It’s crowded, and remember, we’re dealing with a pandemic. And so we’re dealing with restrictions on physical distancing and the like, but the mattresses, the blankets are actually selectively chosen so that they’re safest for the children,” he told “CBS This Morning.” “What we don’t want to do is have a, maybe a traditional mattress with fabric, because it breeds the lice and other conditions,” he said, adding that a “Border Patrol station is no place for a child.” The administration’s focus now is on expanding capacity at its facilities and speeding up the processing of unaccompanied children that would allow them to move out of the government’s care more quickly, officials said Thursday. That includes altering Covid protocols in ways that would increase the number of people allowed inside each facility, opening new facilities and paying for children’s flights or transportation to be reunited with family members or guardians. In Dallas, local immigration attorneys are on standby to provide legal assistance to children arriving at the center, said Michelle L. Saenz-Rodriguez, an immigration attorney based in the city. “We have dozens of immigration attorneys chomping at the bit,” she told CNN. FEMA officials said the Dallas facility, which can hold up to 2,300 people, is currently sheltering 200 boys between the ages of 15 and 17. A Red Cross spokesperson said the facility is being staffed with dozens of volunteers around the clock, and more migrants were expected to arrive Thursday evening. Each migrant is tested for Covid-19 before departing Border Patrol facilities for HHS shelters, FEMA said. At a temporary shelter facility for children in Midland, Texas, FEMA officials said 481 unaccompanied boys between the ages of 15 and 17 were also being housed. That facility can hold up to 700 people.