DETROIT (AP) — At least two Detroit students attending summer school have tested positive for the coronavirus after a judge ordered tests as a condition for attendance in the voluntary classes, officials said.

The students were told to self-quarantine with their families, The Detroit News reported Friday.

More than 250 students have been tested since U.S. District Judge Arthur Tarnow’s order Tuesday. The Detroit district has said more than 600 students have been attending in-person classes since July 13. There’s also an online option.