A D.C. federal judge on Thursday ordered the Biden administration to stop turning away migrant families seeking asylum at the border under a public health directive.

However, he froze the effect of his ruling for two weeks to give the administration time to appeal.

In a 58-page ruling, Judge Emmet G. Sullivan of the U.S. District Court for the District of Columbia said the federal government does not have the authority to rapidly “expel” families who entered the U.S. under a health order known as Title 42 without considering their claims for protection.

The public health law behind Title 42 allows the government to “prohibit … the introduction of” people to the country. Citing the Merriam-Webster Dictionary definitions of “prohibit,” Sullivan concluded that this statute does not permit the expulsion of those who have already entered.

He also found that the migrant families covered by the litigation would likely be placed in harm’s way if they continue to be subjected to the expulsion policy.

“Plaintiffs have provided ample unrebutted evidence demonstrating that they are collectively deprived of certain statutory procedures to seek protection under the Title 42 Process, and they face real threats of violence and persecution if they were to be removed from the United States,” Sullivan wrote.

The decision marks a victory for the American Civil Liberties Union and other advocacy groups which launched this legal challenge to Title 42 in January during the final weeks of the Trump administration.

The advocates spent months in settlement negotiations with the Biden administration after it took office but ultimately decided to resume the litigation after the administration signaled it had no imminent plans to rescind Title 42.

“President Biden should have ended this cruel and lawless policy long ago, and the court was correct to reject it today,” Omar Jadwat, director of the ACLU’s Immigrants’ Rights Project, said in a statement.

The analysis in Sullivan’s opinion Thursday was not entirely surprising. Last year, following an earlier suit by the ACLU on behalf of migrant children traveling alone to the border, Sullivan offered similar reasoning to block the Trump administration from using Title 42 to expel unaccompanied minors. The D.C. Circuit agreed to temporarily lift that ruling, but the Biden administration ultimately decided to officially exempt children who cross the border without their parents from Title 42.

While Sullivan’s latest ruling now bars the federal government from expelling families under Title 42, Sullivan stayed the effect of his own ruling for 14 days to give the administration a chance to request relief from the D.C. Circuit.

The ruling is also limited to migrant families with at least one minor child, meaning the administration may continue to expel single adults under Title 42.

The Justice Department declined to comment on the ruling. The Department of Homeland Security didn’t immediately return a request Thursday for comment.

It’s unclear how the administration will respond to the court’s ruling. DHS has already scaled back its use of Title 42 against migrant families, citing the Mexican government’s refusal to accept them, particularly those with young children, because of capacity restraints.

Of the roughly 86,000 people who crossed the border as part of family units in August, more than 70,000 were allowed into the U.S. to continue their immigration cases, according to government statistics. In contrast, of the approximately 103,000 single adults encountered last month, roughly three-quarters were expelled under Title 42.

The decision marks the latest court blow to the Biden administration on immigration. Federal judges in Texas have ruled against the administration’s deportation moratorium and the Obama-era Deferred Action for Childhood Arrivals program.

A federal judge also recently ordered the administration to reinstate a Trump-era program requiring asylum-seekers to wait in Mexico for decisions in their U.S. immigration court hearings, after the Biden administration attempted to terminate the policy.