Miami (AFP) – A US federal judge on Thursday barred the Trump administration and Florida state government from bringing any new migrants to the detention center known as "Alligator Alcatraz" and ordered much of the site to be dismantled, effectively shuttering the facility.

Florida's government swiftly announced it would appeal the decision.

The detention center was hastily assembled in just eight days in June with bunk beds, wire cages and large white tents at an abandoned airfield in Florida's Everglades wetlands, home to a large population of alligators.

President Donald Trump, who has vowed to deport millions of undocumented migrants, visited the center last month, boasting about the harsh conditions and joking that the reptilian predators will serve as guards.

The White House has nicknamed the facility "Alligator Alcatraz," a reference to the former island prison in San Francisco Bay that Trump has said he wants to reopen.

The center was planned to hold 3,000 migrants, according to Homeland Security Secretary Kristi Noem.

But it has come under fire from both environmentalists and critics of Trump's crackdown on migration, who consider the facility to be inhumane.

The new ruling on Thursday by District Judge Kathleen Williams comes after a lawsuit filed against the Trump administration by Friends of the Everglades and the Center for Biological Diversity.

The environmental groups argue that the detention center threatens the sensitive Everglades ecosystem and was hastily built without conducting the legally required environmental impact studies.

Earlier this month, Williams had ordered further construction at the center to be temporarily halted.

Now she has ordered the Trump administration and the state of Florida -- which is governed by Republican Ron DeSantis -- to remove all temporary fencing installed at the center within 60 days, as well as all lighting, generators and waste and sewage treatment systems.

The order also prohibits "bringing any additional persons onto the... site who were not already being detained at the site."

Several detainees have spoken with AFP about the conditions at the center, including a lack of medical care, mistreatment and the alleged violation of their legal rights.

"They don't even treat animals like this. This is like torture," said Luis Gonzalez, a 25-year-old Cuban who called AFP from inside the center.

He recently shared a cell with about 30 people, a space enclosed by chain-linked fencing that he compared to a chicken coop.

The Trump administration has said it wants to make this a model for other detention centers across the country.