Minnesota Attorney General Keith Ellison said Wednesday the state's public schools should not block students from graduation ceremonies because of outstanding lunch debt.

Ellison said his office had issued the policy at the request of Minnesota Education Commissioner Mary Cathryn Ricker.

"Districts can collect. We're not saying they can't collect," Ellison said. "But they can't use graduation as a cudgel or a barrier for kids and families. And I think that just makes common sense."

Ellison said there were reports that some districts in the state were blocking students from graduation ceremonies because of outstanding meal fees.

Lunch debt has been controversial for years, following reports that some districts in the state were taking away lunches from students who owed money.

There also have been a succession of campaigns, most recently by Valerie Castile, the mother of Philando Castile, to pay off the debt of students around the state.

Before he was shot to death by a St. Anthony police officer, Philando Castile worked in the lunchroom of a St. Paul Elementary School. Valerie Castile won a multimillion dollar settlement, which she has used in part to pay students' lunch debts.

Ellison said the opinion will become state policy, barring a lawsuit or court decision to the contrary.

"Graduation is a matter of academic achievement, and that's what it should stay. It should not be oh, and you paid your student lunch fee, too," Ellison said in an interview.