WASHINGTON — The first U.S. military flight to deport migrants from the United States to Guantanamo Bay has departed and is expected to land Tuesday evening, two U.S. officials said. It is the first step in an expected surge in the number of migrants sent to the Navy base in Cuba, which for decades was primarily used to detain foreigners associated with the Sept. 11, 2001, attacks.

President Donald Trump has eyed the facility as a holding center and said it has the capacity to hold as many as 30,000.

Defense Secretary Pete Hegseth, who was assigned to Guantanamo Bay when he was on active duty, has called it a “perfect place” to house migrants. Additional U.S. troops have arrived at the facility in the past few days to help prepare.

Amy Fischer, director of the Refugee and Migrant Rights Program at Amnesty International USA, decried the use of Guantanamo to house migrants.

“Sending immigrants to Guantanamo is a profoundly cruel, costly move. It will cut people off from lawyers, family and support systems, throwing them into a black hole so the U.S. government can continue to violate their human rights out of sight. Shut Gitmo down now and forever!” Fischer said in a statement.

US Flew Indian Migrants to India Monday

In addition, the U.S. flew Indian migrants back to India on Monday, and that flight was still in progress as of midday Tuesday, one of the officials said. The officials spoke on the condition of anonymity to provide details not yet made public.

There had previously been seven deportation flights, to Ecuador, Guam, Honduras and Peru. In addition, Colombian officials flew to the U.S. and took two flights of migrants back to their country.

There are approximately 300 service members supporting the holding operations at Guantanamo Bay, and the numbers will fluctuate based on the requirements of the Department of Homeland Security, which is the lead federal agency. At least 230 of those service members are U.S. Marines from the 6th Marine Regiment, who began deploying on Friday.

There are more than 725,000 immigrants from India living in the U.S. without authorization, the third most of any country after Mexico and El Salvador, according to the Pew Research Center.

Recent years have also seen a jump in the number of Indians attempting to enter the country along the U.S.-Canada border. The U.S. Border Patrol arrested more than 14,000 Indians on the Canadian border in the year ending Sept. 30, which amounted to 60% of all arrests along that border and more than 10 times the number two years ago.

CNN was first to report on the flights.