(Bloomberg) -- Walmart Inc. is expanding an effort to use robotics to speed up online grocery orders in its battle with Amazon.com Inc. in the fast-growing sector.

The company will build dozens of small warehouses, ranging from 20,000 to 35,000 square feet, within or next to a store to lower grocery fulfillment times, Walmart said. The world’s largest retailer unveiled its first such facility about a year ago. The company declined to provide financial specifics, such as cost savings, on the project.

Grocery sales are booming online after the pandemic pushed Americans to avoid physical stores. As the country’s biggest seller of food, Walmart is trying to defend that business and maintain customers. Speedy grocery delivery is also core to Walmart+, its fledgling subscription offering that competes with Amazon’s popular Prime membership.

“What we want to do is fill as many orders as we can,” said Tom Ward, Walmart’s senior vice president of customer product. “The system allows us to pick orders and dispense them with great speed.”

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