A federal judge on Friday said she doesn’t want a sudden, large-scale release of immigrant children from U.S. government custody but wants to know why they’re still being held as the coronavirus spreads.

U.S. District Judge Dolly Gee in Los Angeles said she wants to be sure immigrant children who were caught crossing the U.S.-Mexico border alone are released to suitable sponsors in an orderly fashion and aren’t put in danger. But she said she wants children out of government-contracted facilities who have been held longer than they should.

Gee didn’t immediately issue a final ruling during the teleconferenced hearing, which came after immigrant advocates asked her to order the prompt release of immigrant children over coronavirus concerns.

The Office of Refugee Resettlement, which is part of the Department of Health and Human Services, said four children in its custody in New York tested positive for the coronavirus, as well as eight staff, contractors or foster parents in New York, Washington and Texas.

The office is tasked with the custody and care of immigrant children caught traveling across the border without parents or a guardian. It contracts with shelters across the country to house these children until they can be released to fitting sponsors, most often their relatives in the United States.

There are currently about 3,500 children in the office’s custody.

For most people, the new coronavirus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia and death. The vast majority of people recover.