Just eight days after returning to the White House last year, President Trump announced plans to turn the U.S. military base in Guantanamo Bay, Cuba, into a massive detention center to hold 30,000 detainees facing deportation as part of his aggressive crackdown on illegal immigration. 

But a CBS News review of internal government documents and information provided to Congress shows the detention facilities at Guantanamo Bay are sitting mostly empty over a year later, even though the highly publicized operation is projected to cost the American military over $70 million.

On May 11, the U.S. government was holding just six immigration detainees at the Guantanamo Bay Naval Base, all of them nationals of Haiti, according to federal documents obtained by CBS News. Over the past year, the documents show, 832 immigration detainees have been transferred to the base on more than 100 flights.

In fact, there are significantly more government employees assigned to the immigration detention operation at Guantanamo than detainees, according to the documents. This week, government employees outnumbered detainees roughly 100 to 1.

Figures provided to Congress indicate the Department of Defense has 522 personnel to assist with immigration detention at Guantanamo. The internal federal documents show there are around 60 U.S. Immigration and Customs Enforcement and non-military staff assigned to the mission, too. 

Information provided by the Department of Defense to Democratic Sen. Elizabeth Warren in April also shows the Guantanamo immigration detention effort is expected to cost $73 million, just for the U.S. military. That is an increase from the previously publicly reported estimate of $40 million.

Mr. Trump said in January 2025 that officials would set up 30,000 detention beds at Guantanamo. But the internal federal documents indicate the base's capacity to hold immigration detainees is limited to roughly 400 beds. On May 11, fewer than 2% of the beds were occupied.

Together with the numbers provided to Congress, the documents shed light on the status of the controversial and largely secretive effort to hold civil immigration detainees at Guantanamo, where the indefinite detention of post-9/11 terrorism suspects gained infamy over allegations of abuse, due process violations and torture.

In a statement to CBS News, Warren, who received the projected cost for the Guantanamo operation, accused President Trump and Defense Secretary Pete Hegseth of "wasting billions in taxpayer funds on a cruel immigration agenda."

CBS News has reached out to the Pentagon and the Department of Homeland Security for comment, including on whether the Trump administration plans to continue the operation to hold immigrant detainees at the naval base.

"Political theater"

Publicly, the Trump administration has released scant details about its operation to hold those awaiting deportation at the Guantanamo base, which sits on Cuban land that the U.S. has long argued is being leased. The Cuban government alleges the arrangement is illegal.

Before the second Trump administration, the U.S. government, under Republican and Democratic presidents, used Guantanamo to house some migrants intercepted at sea, including tens of thousands of Haitians during the Clinton administration. 

But in February 2025, officials began sending groups of detainees arrested by ICE in the U.S. to Guantanamo, so they could be held there pending their deportation. Initially, Mr. Trump and his top aides vowed to send the "worst" detainees and "high-priority criminal aliens" to Guantanamo. But subsequent reporting found that was not entirely accurate.

Soon after the effort started, CBS News revealed Guantanamo was being used to hold both migrants with alleged gang or criminal histories, and detainees categorized as "low-risk" because they lacked serious criminal records — or any at all. Then, in April 2025, CBS News disclosed that the internal government memo governing the operation gave officials wide-ranging discretion to decide who to send to Guantanamo, including the ability to transfer non-criminal detainees there.

Officials have been housing the detainees considered to be "low-risk" at the Migration Operations Center, a barrack-like facility that had previously held asylum-seekers intercepted at sea. Meanwhile, those deemed to be "high-risk" immigration detainees have been detained at Camp VI, a section of the post-9/11 prison complex that still holds some terrorism suspects.  

The legality of detaining civil immigration detainees at Guantanamo is still being litigated. In December, a federal judge in Washington, D.C., found in a preliminary ruling that the immigration detention effort at Guantanamo was "impermissibly punitive" and likely unlawful, but stopped short of blocking the operation. 

Lee Gelernt, the American Civil Liberties Union lawyer who filed the lawsuit, said "the use of Guantanamo is nothing more than political theater like so many other administration policies." 

"Not only is the Trump administration's use of Guantanamo unprecedented and illegal, but it serves no legitimate policy goal given the financial and logistical burdens of using this notorious military base for immigration purposes," Gelernt said.

Theresa Cardinal Brown, a former DHS immigration official under presidents George W. Bush and Barack Obama, said the Trump administration set up Guantanamo and other controversial facilities, such as "Alligator Alcatraz" in Florida, to push people in the U.S. illegally to self-deport and deter others from entering the country unlawfully. 

Cardinal Brown said Guantanamo's deterrence effect is difficult to measure, beyond the low levels of illegal crossings at the U.S.-Mexico border. But she said it's clear the operation has been costly. 

"Everything has to be shipped in there, right? It's not like we're importing things from Cuba," Cardinal Brown said. "Everything has to come from a U.S. source to that military installation. It's going to be much, much more expensive."