HOUSTON (AP) — An appeals court refused Sunday to allow the Trump administration to resume detaining immigrant children in hotel rooms before expelling them under rules adopted during the coronavirus pandemic.

Three judges on the 9th U.S. Circuit Court of Appeals left in place a lower court’s order that requires the U.S. to stop using hotels in most situations to detain children unaccompanied by a parent. The judges denied the U.S. government’s request for a stay of that order.

Border agents since March have placed at least 577 unaccompanied children in hotel rooms before expelling them from the country without a chance to request asylum or other immigration protections. The Trump administration argues it has to expel most people crossing the border due to public health considerations. Advocates for immigrants accuse the administration of using the coronavirus as a pretext to restrict immigration.

“It is a sad fact that court involvement was needed once again to ensure the basic safety of children,” said Leecia Welch, an attorney with the National Center for Youth Law.

The appeals court judges were sharply critical of the administration during oral arguments, questioning why children in the hotels were not guaranteed access to lawyers and why the government wasn’t using existing youth shelters that have thousands of empty beds. Those shelters offer legal services as required under a longstanding court settlement known as the Flores agreement.

A spokeswoman for the Justice Department did not immediately respond to a request for comment Sunday.

Justice Department lawyer Scott Stewart argued that the Flores agreement doesn’t apply to children detained in hotels before expulsion.

“Sometimes, you know, letting people have lawyers even if you’re not obliged to might be a good idea,” said Judge William A. Fletcher, an appointee of President Bill Clinton. Fletcher added it was “an argument you may be about to lose as to whether or not the Flores agreement applies.”

Stewart said the government’s policy of expelling unaccompanied children was part of a “comprehensive, systematic approach” to fight the coronavirus.

“The idea is turn away as quickly as possible, at the border, potential vectors of infection,” he said, adding that a variety of factors led to some children being detained for weeks.

U.S. District Judge Dolly Gee’s Sept. 4 order said hotel detention violated “fundamental humanitarian protections” and said the Trump administration had not demonstrated that using hotels would prevent the spread of COVID-19.

Under the Flores agreement and federal anti-trafficking law, most unaccompanied immigrant children who cross the border, with or without authorization, are supposed to be transferred to government shelters.

The Trump administration has set aside that practice during the pandemic. Instead, it has hired contractors to confine children and families to hotel rooms until they can be expelled. Lawyers who work with immigrant children have said they often don’t know who is being detained and where.

“The problem is we’re seeing children held for far longer than a few days, in some cases up to a month, in a hotel,” said Carlos Holguin, a lawyer for the Center for Human Rights and Constitutional Law who opposed the Justice Department’s position.

In total, the U.S. has expelled at least 147,000 people since March, including 8,800 children unaccompanied by a parent, according to government figures filed in court in September. Most are not detained in hotels. Many of those people have been directly sent back across the U.S.-Mexico border. Other people, including unaccompanied children, are held for days or weeks in Border Patrol facilities unequipped for long-term detention before they are taken to deportation flights.