Amazon.com Inc won partial dismissal of a U.S. Federal Trade Commission lawsuit accusing it of maintaining illegal monopolies, though the details of the ruling by a federal court in Seattle on Monday were not immediately clear.

The FTC has accused the online retailer of using anti-competitive tactics to maintain dominance among online superstores and marketplaces. Amazon asked U.S. District Judge John Chun to dismiss the case in December, saying the FTC had raised no evidence of harm to consumers.

Last year, the FTC alleged Amazon.com, which has 1 billion items in its online superstore, was using an algorithm that pushed up prices U.S. households paid by more than $1 billion. Amazon has said in court papers it stopped using the program in 2019.

Chun issued a sealed ruling, partially granting Amazon's motion. The FTC will be allowed to continue to pursue any claims the judge did not permanently dismiss, court records showed.

Chun also ruled the case will be tried in two parts, rejecting Amazon's bid to have the FTC present evidence of the alleged violations and its proposed remedies in the same trial.

A spokesperson for the FTC declined to comment on the order. An Amazon spokesperson did not immediately respond to a request for comment.

In its complaint last year, the FTC claimed Amazon hampers competition, in part by pushing sellers to use its advertising and fulfillment services. Amazon argued in its motion to dismiss the case that its price-matching and Prime shipping services benefit consumers and are examples of its efforts to compete with thousands of online and brick-and-mortar retailers.

The case is one of five blockbuster lawsuits where antitrust regulators at the FTC and U.S. Department of Justice are going after Big Tech. Facebook owner Meta Platforms and Apple are both being sued, and Alphabet's Google is facing two lawsuits, including one where a judge recently found it unlawfully thwarted competition among online search engines.

The Amazon.com case is an important one for FTC Chair Lina Khan, who has long pushed to challenge the power of the huge online retailer. In 2017, Khan wrote an influential academic article arguing the company's structure and practices posed anticompetitive concerns and had escaped antitrust scrutiny.