The Biden administration faces growing immigration concerns as thousands of migrants make their way to the southwest. On Thursday, federal officials said there are more than 14,000 unaccompanied children in custody.

Migrants making their way to the border in increasing numbers didn't catch some officials off guard. The Associated Press noted that the reversal of Trump administration immigration policies caused some top immigration officials to worry that there would be a surge in immigration.

There was also a surge in 2019 and 2020, President Joe Biden said in an interview. He also dissuaded migrants from crossing the border.

"Yes, I can say quite clearly, 'Don't come over,'" Biden told ABC News' George Stephanopoulos.

The federal government has sought to move children out of U.S. Customs and Border Protection custody and into shelters and centers operated by the Health and Human Services Department.

There were around 9,300 children at the border in February, which is a 63% increase from January, along with an additional 19,000 family members, a 168% increase, the Pew Research Center reported.

“They should have forecasted for space (for young migrants) more quickly,” said Ronald Vitiello, a former acting director of Immigration and Customs Enforcement and chief of Border Patrol. “And I think in hindsight, maybe they should have waited until they had additional shelter space before they changed the policies.”

Republican lawmakers and right-leaning media have attacked the Biden administration's immigration policy. On Friday, Sen. Ted Cruz, R-Texas, posted on Twitter that he is bringing 15 U.S. senators to the border at about the same time that a bipartisan group of senators visited border facilities with Department of Homeland Security Secretary Alejandro Mayorkas.

Housing children has been a major issue in this border “crisis,” which is why Biden called in FEMA, the Federal Emergency Management Agency, to help open additional facilities for housing.

“We will have, I believe, by next month enough of those beds to take care of these children who have no place to go,” Biden told ABC News. “Let’s get something straight though. The vast majority of people crossing the border are being sent back ... immediately sent back.”

Sen. Chris Murphy, D-Conn., told "Fox News Sunday" host Chris Wallace that Biden "inherited a mess from [President] Donald Trump in terms of immigration, and he’s trying to fix it in a humane way."

Biden has proposed an eight-year path to citizenship for undocumented immigrants. Roughly 11 million people live in the U.S. without legal status.

Joe Biden's campaign flag is seen at a migrant camp in Tijuana on the US-Mexico border
Joe Biden's campaign flag is seen at a migrant camp in Tijuana on the US-Mexico border AFP / Guillermo Arias