Ferguson, Missouri, and a second St. Louis suburb are being accused in separate lawsuits of operating a "debtors' prison scheme," illegally jailing poor people who are unable to pay traffic tickets or fines tied to other minor offenses.

The lawsuits, filed on Sunday in U.S. District Court in St. Louis by 20 black residents, allege that officials in Ferguson and neighboring Jennings have routinely been abusing and exploiting impoverished individuals to boost city revenues. The plaintiffs are seeking class-action status for the cases.

The plaintiffs claim the money they are told they owe is often arbitrarily modified, and the individuals are frequently kept locked in a cycle of jail time and indebtedness to the municipal courts as late fees and surcharges are added to initial fines.