President Donald Trump’s failed plan to detain up to 30,000 migrants at Guantánamo Bay has cost taxpayers millions of dollars.

Trump’s administration has detained just 300 migrants at the U.S.-operated facility in Cuba over the last two months. But now, all migrants detained at the facility have since been flown out, The Independent learned.

The failed operation cost taxpayers at least $16 million, Representative Sara Jacobs told ABC News after visiting the site.

"It was clear that this was entirely for optics and the fact that Donald Trump wanted to be able to say that he was sending immigrants to Guantánamo Bay, with all of its history of human rights abuses and with no actual operational value," Jacobs said.

The government spent $3 million alone to construct tent structures, which are still not functional and were never used, CNN reports.

Federal officials told ABC News that 195 tents were built, which could house up to 500 migrants. The tents, however, lacked necessities required by Immigration and Customs Enforcement, such as air conditioning.

They’re now expected to stay up for potential use during hurricane season.

Shipping all immigrants out does not necessarily mean the operation is over; two federal officials told the Associated Press that the s that the administration may use the facility again in the future. For instance, Trump has vowed to send migrants who have been deemed dangerous to the facility, such as members of criminal organizations like Tren de Aragua, a Venezuelan gang, CNN reports. But presumably millions of dollars more would be required to make the facility ususable.

For now, further use of Guantánamo Bay isn’t a “primary course of action” and officials are looking to use US military bases to house migrants, according to CNN.

Civil rights groups have been fighting the Trump administration over treatment of immigrants, with one lawsuit alleging migrants were mistreated and subjected to “a living hell” while they were detained at Guantánamo Bay.

Jennifer Babaie, director of advocacy and legal services with Las Americas Immigrant Advocacy Center, said last month Guantánamo is a “breeding ground for violence, abuse and neglect.”

“Many of these men have already been subjected to countless human rights abuses and due process violations,” she said.

“Keeping them in Guantánamo without regular access to lawyers and loved ones while at the same time spreading unfounded accusations against them all on the basis of what they look like and where they come from, is dangerous, violent, and completely unacceptable,” she added.

Before they were removed, more than 100 migrants who were considered “higher-threat” were detained inside Camp IV. The facility resembles those used to house prisoners of war, according to sworn statements from Homeland Security and U.S. Army personnel. Other “lower-threat” detainees were held “in and around” a barracks-like “Migrant Operations Center.”

The American Civil Liberties Union and other advocacy groups also argued this week that moving migrants to Guantánamo Bay violates the Immigration and Nationality Act, the Associated Press reports. Meanwhile, the White House has maintained it has the authority to do so.

The Independent has contacted the White House for comment.

With reporting from Alex Woodward.

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