The Trump administration said Thursday it has located 146,000 unaccompanied migrant children who crossed the U.S.-Mexico border during the Biden administration and were later released to sponsors, while nearly 300,000 children remain unaccounted for.

Acting Attorney General Todd Blanche and Homeland Security Secretary Markwayne Mullin announced the figures during a press conference at the Justice Department in Washington, saying the number of children located has increased from about 22,000 last summer. 

"We found 146,000 kids so far — 146,000 kids. We still have nearly 300,000 missing," Mullin said.

Mullin criticized the Biden administration's handling of unaccompanied minors, alleging that inadequate oversight allowed hundreds of thousands of children to be released without sufficient follow-up.

"When we start digging into these cases, and you start hearing the absolute horrific things that took place underneath the Biden administration, either true neglect at best and criminal at worst, to allow 450,000 kids to go missing throughout this country," Mullin said.

According to administration officials, more than 500,000 unaccompanied migrant children entered the United States during the Biden administration after crossing the southern border without a parent or guardian.

The children were transferred to the care of the Department of Health and Human Services and later released to sponsors in the United States.

The Trump administration has made locating those children a priority, with federal agencies working to identify their whereabouts and determine whether they are safe.

Officials did not provide additional details Thursday on how the children were located or the status of efforts to find those who remain unaccounted for.