Customers shop at a Whole Foods store in New York City, U.S., August 28, 2017. REUTERS/Brendan McDermid

(Reuters) - Amazon.com Inc said on Thursday it would start delivering Whole Foods groceries via its fast-shipping Prime Now service in select U.S. cities, and plans to expand it across the country this year.

The online retailing behemoth will add Whole Foods to its one-hour and two-hour delivery service in Austin, Cincinnati, Dallas and Virginia Beach, it said in a statement.

Amazon Prime members will receive two-hour delivery for free and one-hour delivery for $7.99 on orders of $35 or more, the company said.

Amazon shook up the industry with its $13.7 billion acquisition of Whole Foods last year, prompting traditional grocery sellers to look for ways to profitably deliver fresh food and shelf-stable pantry items.

In recent months, the world’s largest retailer Walmart Inc, healthy food supermarket chain Sprouts Farmers Market and the largest traditional supermarket operator, Kroger Co, have bolstered their delivery offerings in the United States.

Last month, Amazon raised the monthly fee for Amazon Prime by $2, the first increase of Prime fees in almost four years.