Toys R Us, the world's largest toy retailer, said its U.S. stores will carry Amazon.com's Kindle electronic reader and related accessories starting July 31.

The news came as more retailers attempt to grab a bite of growing e-reader sales.

Earlier on Wednesday, office supplies retailer OfficeMax Inc said it will sell Barnes & Noble Inc's Nook e-readers at the end of this month.

Toys R Us plans to give a free $10 Toys R Us gift card to shoppers buying the popular e-reader at its stores from July 31 through August 6, while supplies last, the company said on Wednesday.

Toys R Us will carry models including Kindle Wi-Fi in graphite, Kindle 3G + Wi-Fi in graphite and Kindle Wi-Fi with Special Offers. The accessories will range from leather covers to power adapters.