MIAMI (NewsNation Now) — Thousands of children are currently in U.S. custody after crossing the southern border as unaccompanied minors.

18,046 children are either in Customs and Border Patrol or Health and Human Services custody as of March 25, according to the latest figures from the Biden administration.

As many as 40% of these kids have a parent or legal guardian somewhere in the United States. HHS works to unite those children with parents but until they remain in federal custody.

More than 2,000 miles from the U.S. Mexico border, Nora Sandigo is working the phones in her house on the outskirts of Miami. Her goal? Cut down on the significant backlog of children awaiting reunification with their parents.

NewsNation caught up with her as she was in the midst of making calls.

“(It’s) really busy. Because more and more children are coming to the country and the families are really worried,” said Sandigo.

Nora’s home office is like a make-shift call center with six phone lines. Through her non-profit, Nora Sandigo Children Foundation, she connects unaccompanied children in immigration detention with families in the United States.

Normally she estimates she gets about 25 calls a day. Right now, she’s getting more than 50.

Most of the calls are from parents already inside the U.S. trying to find their kids. Along with kids trying to find their parents.

“They cry and cry. They say, ‘mom, I want to be with you. I miss you. I need you. Please help me, I want to go with you.’ They cry and cry. Most of the time, you don’t understand what they are saying because they are crying. Both sides, mother and kids, at the same time,” explained Sandigo.

President Biden talked about the challenge of reuniting unaccompanied children with their families at Thursday’s news conference.

“The vast majority of people under the age of 18 coming to the United States come with a telephone on a wristband or a telephone number in their pocket. A mother, a father, a grandpa or grandma,” said Biden. “We have set up a system now where within 24 hours a phone call is made as that person is crossing the border.”

Sandigo told NewsNation that she has seen it frequently take a lot longer than 24 hours.

“I don’t think this is exactly the case. At least in the cases, we have seen. Most of the children are there for more – sometimes 72 hours with no communication with their family,” commented Sandigo.

In one case, a mother of a 3- and 5-year-old was trying to find her children. Her kids had been in detention since Feb. 22 and she was in Austin, Texas.

Sandigo works with volunteer lawyers who work as a liaison for the families and CBP to prove that the guardians are legitimate so reunions can happen. She says the last time she can remember it being this busy was in 2019 when there was another surge of unaccompanied minors arriving at the border.