Amazon, facing backlash from critics who say cashless stores discriminate against the poor, will soon accept cash at all its stores.

The online shopping giant has more than 30 stores that don't accept cash, including its book shops and Amazon Go convenience stores.

Amazon (AMZN) confirmed it is working to accept cash, but wouldn't say when that would happen.

Critics say cashless stores discriminate against those that don't have credit cards or bank accounts. Philadelphia became the first city to ban cashless stores earlier this year; New Jersey passed a statewide ban; and New York, San Francisco and other cities are considering similar laws.

The news was first reported by business news website CNBC.