FILE PHOTO: Amazon boxes are seen stacked for delivery in Manhattan, New York, U.S., January 29, 2016. REUTERS/Mike Segar/File Photo

(Reuters) - Amazon.com Inc said on Wednesday it was expanding its discounted Prime membership offer to Medicaid members, the U.S. government’s health insurance program for the poor.

The move from the e-commerce giant comes nine months after it said it would offer a discount on its popular Prime subscription service for shoppers who receive U.S. government aid.

To qualify for the discounted $5.99 monthly Prime membership, customers must have a valid Electronic Benefits Transfer or Medicaid card and can renew it annually for up to four years, the company said.

The $12.99-per month or $99-per-year prime service offers users added perks like low prices and faster delivery for certain purchases and shipped over 5 billion items worldwide last year.

Any push by Amazon into poorer demographics comes at a time when traditional brick-and-mortar suppliers like Walmart Inc have been fighting the online shopping giant’s arrival by seeking to attract more high-spending shoppers.

The Medicaid connection may also stir more nerves among healthcare companies worried about tentative moves by Amazon to sell and distribute some medical supplies and drugs.