A divided 5th US Circuit Court of Appeals ruled that immigrants cannot be held in mandatory detention for more than 90 days without a bond hearing.
It limits a key part of the Trump administration's immigration policy.
The Trump administration defended its interpretation of immigration law.
Thousands of immigrants facing deportation in Texas, Louisiana and other states covered by the 5th US Circuit Court of Appeals cannot be held for more than 90 days without an opportunity to seek release on bond, the court ruled on Thursday, limiting a key element of the Trump administration's immigration detention policy.
The 2-1 ruling by the New Orleans-based 5th US Circuit Court of Appeals could affect thousands of people detained by US Immigration and Customs Enforcement (ICE) in states within the court's jurisdiction, including Texas and Louisiana, as part of President Donald Trump's immigration crackdown.
The decision marks a shift from an earlier ruling by a different panel of the same court, which in February became the first in the country to endorse the administration's interpretation of federal immigration law allowing mandatory detention of certain non-citizens living in the United States. That ruling, however, did not address whether the Fifth Amendment's due process protections require detainees to be given an opportunity to seek release through a bond hearing before an immigration judge.
Writing for the majority, US Circuit Judge Leslie Southwick said the US Supreme Court had made clear in 2001 that the Constitution's due process protections extend to everyone within the US, including the two Mexican citizens and one Honduran whose cases were before the court.
"It is part of the historic majesty of this long-ago founding charter that it makes no exceptions in providing basic rights to those within our boundaries, including a right to be heard when personal liberty is taken," wrote Southwick, who was appointed by Republican President George W. Bush.
US Circuit Judge Cory Wilson, a Trump appointee, dissented, saying "the majority marginalizes the Constitution's express grant of plenary authority over immigration matters to Congress."
Rebecca Cassler, a lawyer representing the migrants at the American Immigration Council, welcomed the ruling.
"They are delighted that the panel recognized the core constitutional principle that the due process clause does not allow the government to lock them away indefinitely," she said in a statement.
The US Department of Homeland Security, which oversees ICE, said it disagreed with the ruling "and is confident in its legal position regarding mandatory detention." The department noted that it had asked the US Supreme Court last week to review a similar ruling by another federal appeals court.
Under federal immigration law, "applicants for admission" to the United States are subject to mandatory detention while their immigration cases are pending and are generally ineligible for bond hearings.
Last year, the Department of Homeland Security adopted a broader interpretation of the law, arguing that the provision applies not only to people seeking entry at the border but also to non-citizens already living in the United States. The Justice Department's Board of Immigration Appeals adopted that interpretation in September, prompting immigration judges nationwide to begin ordering mandatory detention in such cases.
Federal appeals courts have since split over whether the administration's interpretation is lawful, leading the Trump administration to ask the Supreme Court to resolve the issue.
