White House Press Secretary Karoline Leavitt said Tuesday the first flights of undocumented immigrants from the U.S. to Guantánamo Bay in Cuba were underway—following an escalation of arrests across the country as part of what President Donald Trump has promised would be the “largest deportation operation” in U.S. history.

Cargo planes from Joint Base Lewis-McChord are being used in the Trump administration’s ramped-up deportation of immigrants in the country illegally, The News Tribune has learned.

As tents went up in Guantanamo Bay, Cuba to hold migrants, attorneys at the Department of Homeland Security and Pentagon were still trying to determine whether it was legal to take the unprecedented step of flying migrants from the US southern border to the facility,