SEATTLE — Amazon Go grew from a single convenience store to four over eight months. A report Wednesday suggests that the retail giant is considering a much faster pace of expansion.

Bloomberg reported that the Seattle company is considering a plan to open as many as 3,000 Amazon Go convenience stores by 2021. That would be an immediate challenge to established chains like 7-Eleven.

The story, citing unidentified people familiar with the matter, said the company was considering different models as it looked to expand Go, weighing whether to include a limited selection of groceries or focus on prepared food pickup.

An Amazon spokeswoman declined to comment on the report.

The first Go store opened to the public at Amazon’s Seattle headquarters in January. Since then, the company has opened two more Seattle sites and one in Chicago, and has confirmed plans for San Francisco and New York stores. The small-format stores — the largest is 2,100 square feet — carry a mix of prepared and packaged food, soft drinks and make-at-home meal kits.

A 3,000-store footprint would catapult Amazon into the ranks of America’s major physical retail chains.

7-Eleven operates about 8,000 stores, according to the National Retail Foundation’s 2017 tally. Amazon rival Walmart operates 5,300, and Kroger, the largest U.S. grocer, runs 3,900 stores.

Amazon bought its way into brick-and-mortar groceries with the $13.5 billion acquisition of the more than 470 Whole Foods Market locations last year. It also operates or plans to open 18 bookstores and a range of smaller pop-up stores in malls and Kohl’s locations.

Amazon, like many secretive technology companies, rarely telegraphs its growth plans. But it has pushed back on past reports that executives had decided on a major expansion of Go.

When The Wall Street Journal reported a year ago that Amazon envisioned opening 2,000 brick-and-mortar grocery stores with different formats, the company took the rare step of denying the report, instead of issuing its usual one-line statement declining to comment on reports of unannounced plans.

“We have no plans to open 2,000 of anything,” a spokesperson said a few days after the newspaper’s story published. “Not even close.”