Amazon is expanding its same-day grocery delivery service to 1,000 cities and towns across the U.S., the company said Wednesday.

The online retail giant plans to expand the service to 2,300 U.S. locations by year’s end in its quest to compete with Walmart.

Customers in more than 1,000 locations now have access to fresh groceries with its free same-day delivery service on orders over $25 for Prime members.