The American Civil Liberties Union says "Bible literacy" classes being taught in some Kentucky public schools may violate the Constitution.

The Courier-Journal reports the state chapter of the ACLU sent a letter to the Kentucky Department of Education requesting it develop teaching guidelines for the classes. Education Department spokeswoman Rebecca Blessing says the agency is working to promote statewide academic standards for the classes.

The ACLU's review found a majority of school districts do not offer the classes. But it said those that do sometimes appear to veer from studying the Bible as a work of literature to studying it in a devotional manner.

The letter advises the education department to monitor classes to ensure they comply with the Constitution or it could face a lawsuit.