DONNA — The Biden administration for the first time Tuesday allowed journalists inside its main border detention facility for migrant children, revealing a severely overcrowded tent structure where more than 4,000 migrants, including children and families, were crammed into pods and the youngest kept in a large play pen with mats on the floor for sleeping.

Young children lie inside a pod at the Donna Department of Homeland Security holding facility, the main detention center for unaccompanied children in the Rio Grande Valley run by U.S. Customs and Border Protection, in Donna, Texas, Tuesday, March 30, 2021. The children are housed by the hundreds in eight pods that are about 3,200 square feet in size. Many of the pods had more than 500 children in them. The Biden administration on Tuesday for the first time allowed journalists inside its main detention facility at the border for migrant children, revealing a severely overcrowded tent structure where more than 4,000 kids and families were crammed into pods and the youngest kept in a large play pen with mats on the floor for sleeping.(AP Photo/Dario Lopez-Mills, Pool)

With thousands of children and families arriving at the U.S.-Mexico border in recent weeks and packing facilities, President Joe Biden has been under pressure to bring more transparency to the process. U.S. Customs and Border Protection allowed two journalists from The Associated Press and a crew from CBS to tour the facility in Donna, Texas, in the Rio Grande Valley.

The facility has a capacity of 250 but more than 4,100 people were being housed on the property Tuesday. Most were unaccompanied children processed in tents before being taken to shelters run by the Department of Health and Human Services and then placed with a family member, relative or sponsor.

The children were being housed by the hundreds in eight pods about 3,200 square feet in size. Many of the pods had more than 500 children in them.

Oscar Escamilla, acting executive officer of the U.S. Border Patrol in the Rio Grande Valley, said 250 to 300 kids enter daily and far fewer leave.

“That number is so lopsided,” said Escamilla.

On Tuesday, journalists watched children being processed. They went into a small room for lice inspection and a health check. Their hair was hosed down and towels were tossed in a black bin marked “Lice.” The minors — many of whom have made long journeys to get to the border, including stretches on foot — were also checked for scabies, fever and other ailments. No COVID-19 test was administered unless a child showed symptoms.

A migrant and her daughter have their biometric data entered at the intake area of the Donna Department of Homeland Security holding facility, the main detention center for unaccompanied children in the Rio Grande Valley, in Donna, Texas, Tuesday, March 30, 2021. (AP Photo/Dario Lopez-Mills, Pool)

Nurse practitioners also gave psychological tests, asking children if they had suicidal thoughts. All shoelaces were removed to avoid harm to anyone.

The children were then led down a green turf hall to a large intake room. Those 14 and older are fingerprinted and have their photo taken; younger children did not.

Then they were taken to a second intake room where they got notices to appear for immigration court. Border Patrol agents asked them if they had a contact in the U.S. and allowed the child to speak with them by phone.

Children were given bracelets with a barcode that shows history of when they showered and medical conditions.

Outside the facility, the roar of construction equipment could be heard along with air conditioning units.