After being stretched by the coronavirus pandemic, the U.S. foster care system has another challenge ahead: an unprecedented number of unaccompanied migrant children coming over the southern border who need care before they can be placed with relatives already living in the U.S.

Customs and Border Protection (CBP) projected in April that as many as 184,000 unaccompanied children could reach the border in the fiscal year 2021. There are an estimated 420,000 children in U.S. foster care.

BORDER CRISIS: 5 UNACCOMPANIED MIGRANT GIRLS FOUND ABANDONED IN TEXAS

"We tried to figure out the pandemic, how to handle it. Now we’re trying to figure out this mass influx of children that are unaccompanied," Irene Clements, executive director of the National Foster Parent Association, told Fox News in an interview. "It's pretty much nationwide there's a lack of foster families to meet the needs, especially during COVID."

Five Republican governors — South Dakota Gov. Kristi Noem, Nebraska Gov. Pete Ricketts, South Carolina Gov. Henry McMaster, Iowa Gov. Kim Reynolds and Wyoming Gov. Mark Gordon — recently told the Biden administration they won't house migrant children through their state foster care systems as the government scrambles to deal with federal facilities that are at capacity. The Biden administration has even asked NASA employees to volunteer at overcrowded border facilites.

Five abandoned migrant girls, all under the age of 7, were discovered Sunday by a Texas farmer on his land in Quemado, near the Rio Grande River.

Five abandoned migrant girls, all under the age of 7, were discovered Sunday by a Texas farmer on his land in Quemado, near the Rio Grande River.

"President Biden has created an immigration crisis on our border with thousands of unaccompanied migrant children coming to our country without their parents or family," Ricketts said in a statement on April 13. "Right now, the Biden-Harris Administration is contacting states to take these children. Nebraska is declining their request because we are reserving our resources for serving our kids. I do not want our kids harmed as the result of President Biden's bad policies."

"South Dakota won't be taking any illegal immigrants that the Biden Administration wants to relocate. My message to illegal immigrants... call me when you're an American," Noem wrote on Twitter on April 14.

Noem spoke at an event to recruit foster and adoptive parents on Tuesday afternoon.

"When I was a little girl, my mom and dad brought a little foster boy into our family, so I grew up with a foster brother," Noem said. "I think that we can do more to support kids and families in crisis [and] helping those families reunify when we can."

South Dakota had 833 foster families as of April 30, and the state announced a new goal of recruiting 300 new families per year to care for the more than 1,700 children in the custody of the Department of Social Services in South Dakota.

South Dakota Gov. Kristi Noem speaks at a Stronger Families Together event on May 11, 2021. (Photo courtesy of Noem's office)

South Dakota Gov. Kristi Noem speaks at a Stronger Families Together event on May 11, 2021. (Photo courtesy of Noem's office) (Photo courtesy of Noem's office)

That number is just a fraction of the 22,103 unaccompanied children in the care of the Department of Health & Human Services as of April 26. The number of children in HHS care has been climbing daily even as the department discharges hundreds of children to vetted sponsors everyday.

BCFS Health and Human Services, one of several nonprofits that shelter unaccompanied minors, told Fox News that the organization does not support any proposals to place migrant children in state-funded foster care.

"From what we know, we see no impact from these decisions as migrant children are not currently placed in and, in our opinion, should not be placed in state-funded foster care systems," BCFS told Fox News in a statement. "We encourage all states to prioritize the quality, availability and funding for the care of displaced children who are US citizens. These are children who have generally been abused and neglected by those who should love them the most and, to that end, deserve and need the support of the public and private sectors in order to survive and have the opportunity for safe and productive lives."

Rosanna Berardi, managing partner at Berardi Immigration Law, told Fox News in an interview that the federal government's strategy in seeking help from states is all wrong and includes no incentives for states to help.

"Where is Congress? Congress needs to fix this problem. This is not a state issue. This is not a presidential executive order issue. This is Congress not having control," Berardi said. "States are saying, 'Hey, wait a minute, we’re clogged already. We have our own problems.'"

The federal government's requests to states were vague and had "no parameters," she said.

"Can the states say no? Probably," Berardi said. "These governors are making hugely political statements, saying we don’t agree with what you’re doing. ... It seems callous at first, but the reality of foster care is these states are drowning on a good day."

However, the National Foster Parent Association's public policy committee chair, Arnold Eby, told Fox News he sees the governors' reactions as "not necessarily politically based."

"It’s not necessarily politically based but more an understanding of your state’s capacity," he said. "Each state has a different capacity with public or private foster care families or facilities. If your state doesn’t have systems or capacity to do that ... I would applaud anybody who makes a decision based on their state not having the capacity to serve."

 In this March 30, 2021, file photo, young minors 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 (CBP), in Donna, Texas. (AP Photo/Dario Lopez-Mills, Pool, File)

 In this March 30, 2021, file photo, young minors 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 (CBP), in Donna, Texas. (AP Photo/Dario Lopez-Mills, Pool, File) (AP Photo/Dario Lopez-Mills, Pool, File)

"Foster parents and the system have been stretched significantly by the pandemic, and foster families are tired," Eby continued. "I know that because we do in-home foster care. We’ve had five children between 5 and 10 for the last five months. It has been an exhausting period of time."

Clements, the group's executive director, said she has advised families interested in working with the federal government to take in unaccompanied children to educate themselves about the level of support and training they'll receive because it varies from state to state.

"It’s kind of crazy right now to even know what the expectations even are. They seem to be all over the place," she said.

CLICK HERE TO GET THE FOX NEWS APP

California's Community Care Licensing Office made headlines in March for reportedly approaching foster parents about holding as many as 26 unaccompanied migrant children in their homes.

"It’s just mind-blowing. … these people really don’t understand what’s going on yet," Clements said. "They're desperate."

Fox News' inquiry to the Administration for Children & Families, part of HHS, was not returned at the time of publication.

Fox News' Griff Jenkins, Houston Keene and Adam Shaw contributed to this report.