President-elect Donald Trump‘s pick for border czar, Tom Homan, underscored the need for the administration to relocate 300,000 missing children in the United States who have become lost amid the nation’s border crisis.

Trump announced Monday that his incoming administration will declare a national emergency to carry out mass deportations of illegal immigrants, which will include using military resources. In previewing the administration’s deportation plans, Homan revealed the three tiers that will guide these deportations, the first being removing those who are national security threats and the second being securing the border.