The Trump administration is considering using large ships, including a 500-foot training vessel and commercial ferries, to transport illegal immigrants to Central and South America as part of its broader effort to carry out mass deportations, according to a report published Thursday.

The preliminary proposal could involve voyages lasting several days and costing millions of dollars per trip, according to two U.S. officials familiar with the discussions. No final decision has been made, and officials have described the idea as hypothetical.

Among the vessels under consideration is the Training Ship Golden Bear, a maritime academy training ship docked in California. Defense Department officials have also contacted companies about potential vessels in Europe, according to the report.

The Department of Homeland Security, which oversees immigration enforcement and deportations, said it is evaluating available resources to support President Donald Trump’s border security agenda.

“DHS is assessing all our resources to maximize efficiency and continue to deliver on President Trump’s mission of securing the homeland for all Americans,” the department said in a statement.

The proposal could shift some deportation expenses from Homeland Security to the Department of Defense. However, the government would still face substantial costs for operating ships, staffing security personnel, and managing detainees during extended voyages.

Sea transportation would also present significant logistical challenges. Officials have not publicly outlined how migrants would be housed aboard the vessels, what security arrangements would be required, or whether destination countries would agree to receive deportees transported by sea.

Claire Trickler-McNulty, a former Immigration and Customs Enforcement official, raised concerns about the practical and legal complications of holding large numbers of people aboard ships for days while traveling through international waters.

The proposal follows the administration’s broader effort to expand deportation operations through multiple methods, including military aircraft and arrangements to send migrants to countries other than their own.

Using ships would also revive memories of past U.S. deportation operations conducted by sea. During the 1950s, the federal government carried out a mass deportation campaign known as Operation Wetback, which included maritime transfers of Mexican nationals. A 1956 incident near Tampico, Mexico, involved migrants jumping from a deportation ship, with five people reportedly drowning.

For now, the ship-based proposal remains under consideration, with unanswered questions about its cost, operational feasibility, and legal authority. The administration has not announced a final plan to begin deportations using the vessels.