About 300 servicemembers have arrived in recent days as the base faces its most drastic changes since the Pentagon opened a prison there after the Sept. 11 attacks.

Guantanamo Bay, a U.S. base in Cuba since 1898, may soon house thousands of detained migrants, following a proposal by the Trump administration.

Human rights groups have accused U.S. authorities of using Guantánamo Bay for decades to detain migrants fleeing Haiti, Cuba and other Caribbean nations.