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.

The Trump administration has carried out 10 deportations on military planes. The flights cost more and move fewer, an El Paso Times analysis found.

Guatemala has pledged a 40% increase in deportation flights carrying Guatemalans and migrants of other nationalities from the United States, President Bernardo Arévalo announced Wednesday during a press conference with US Secretary of State Marco Rubio.