Toys R Us is facing a U.S. antitrust probe over whether the toy retailer used its market clout to stifle discounting by retail competitors and force consumers to pay higher prices for baby products, the Wall Street Journal reported on Saturday.

The Federal Trade commission is looking into whether the retailer violated an 11-year-old FTC order to abstain from anti-competitive practices, the newspaper said, citing people familiar with the matter.

Toys R Us had agreed to the order in 1998, after an administrative law judge found it had forced major toy manufacturers to sell only so-called value packs of several toys or discontinued items to discount shopping clubs like Costco Wholesale Corp .

Those practices prevented consumers from comparing prices and the quality of products and curtailed the effectiveness of the clubs as competitors, the FTC charged.

It was unclear whether the current probe would result in any enforcement action, the newspaper said.

Spokespeople from the FTC and Toys R Us could not be reached for comment.

(Reporting by Brad Dorfman)