A private prison in Kansas could soon be holding migrants as part of President Trump’s promise of mass deportations for those living in the U.S. illegally. (AP Video: Nick Imgram)

The move marks a significant pivot for the Trump administration, which has vowed to deport millions of immigrants living in the country without legal status.

Immigration and Customs Enforcement agents — often dressed in plainclothes — are now arresting immigrants at courthouses nationwide, sometimes moments after their hearings end. Why it matters: The courthouse crackdown is part of a sweeping Trump administration effort to fast-track removals and increase the number of deportations this year — a strategy that's dramatically expanding who gets targeted and how.

Lawyers and relatives of the immigrants detained in a series of workplace raids in Los Angeles were rushing to locate them and intervene before removal.

A group of ICE agents and the migrants they're holding in Djibouti following an order by a U.S. federal judge are at grave risk, an immigration official says.

Migrants are being detained by immigration agents in courthouse hallways nationwide, sometimes moments after pleading their cases, raising alarm among attorneys and advocates who say the practice is turning immigration courts from places of due process into zones of fear.

President Trump said he plans to make changes to his administration's aggressive crackdown on illegal immigration to address worker shortages.

Immigration attorneys tell ABC News that federal agents are arresting migrants at immigration courts -- in some cases after their deportation cases have been dismissed.