The Federal Trade Commission on Wednesday accused online retail giant Amazon of underhanded practices to keep customers enrolled in its Prime program, in a complaint filed in federal court.

The FTC is accusing Amazon of intentionally manipulating consumers into subscribing to Amazon Prime via "coercive or deceptive user-interface designs" known as "dark patterns." 

"Amazon tricked and trapped people into recurring subscriptions without their consent, not only frustrating users but also costing them significant money," FTC Chair Lina Khan said.

She added, "These manipulative tactics harm consumers and law-abiding businesses alike. The FTC will continue to vigorously protect Americans from ‘dark patterns’ and other unfair or deceptive practices in digital markets."

The FTC also claims Amazon intentionally complicated the process for canceling Prime subscriptions, exerting great effort to stop consumers from ending their payments. 

"During Amazon’s online checkout process, consumers were faced with numerous opportunities to subscribe to Amazon Prime at $14.99/month. In many cases, the option to purchase items on Amazon without subscribing to Prime was more difficult for consumers to locate," the FTC wrote in a press statement. 

"In some cases, the button presented to consumers to complete their transaction did not clearly state that in choosing that option they were also agreeing to join Prime for a recurring subscription," the statement added.

The commission claims Amazon's use of dark patterns to manipulate its customers is a violation of both the FTC Act and the Restore Online Shoppers’ Confidence Act.

FTC Bureau of Consumer Protection staff attorneys Jonathan Cohen, Olivia Jerjian, Max Nardini and Evan Mendelson are handling the case.

The case was filed in the U.S. District Court for the Western District of Washington.

FOX Business has reached out to Amazon for comment.