Amazon violated consumer protection law by gathering Prime subscribers' billing information before disclosing the service's terms, a judge ruled, handing the U.S. Federal Trade Commission a partial win.

The ruling by U.S. District Judge John Chun on Wednesday in the case accusing Amazon of deceptive practices to generate Prime subscriptions puts the company at a disadvantage at trial.

The FTC is poised to argue that the online retailer signed up tens of millions of customers for Prime without their consent, and thwarted tens of millions of cancellation bids through complex cancellation methods.

The agency says those actions violated the Restore Online Shoppers Confidence Act (ROSCA).

"Today’s decision affirms that Amazon defrauded American consumers by failing to disclose all terms of prime before collecting consumer’s payment information," said Chris Mufarrige, head of the FTC's bureau of consumer protection. "The Trump-Vance FTC intends to make them whole."

The judge also ruled that two Amazon executives were liable for any violations the FTC proves at trial, while barring Amazon from arguing that ROSCA did not apply to Prime signups. A spokesperson for Amazon did not immediately return a request for comment. The company has denied the accusations.