Apple Inc. said it terminated Epic Games’s App Store developer account in the midst of a legal battle over the iPhone maker’s in-app-purchase rules.

The Cupertino, California-based technology giant had recently threatened to do this after Epic added an option for users of its Fortnite video game to pay Epic directly for in-game upgrades. That avoided a 30 per cent cut that Apple takes through its App Store and broke Apple’s rules.

“We are disappointed that we have had to terminate the Epic Games account on the App Store,” Apple said in a statement. “We have worked with the team at Epic Games for many years on their launches and releases. The court recommended that Epic comply with the App Store guidelines while their case moves forward, guidelines they’ve followed for the past decade until they created this situation. Epic has refused.”

Epic Games did not immediately respond to a request for comment. The company sued Apple earlier this month after Apple pulled Fortnite from the App Store.

A court order last week denied Epic’s motion to force Apple to reinstate Fortnite on the App Store. However, the judge ruled that Apple could not terminate the developer account that Epic uses for Unreal Engine, a graphics technology that is used by many game developers. Apple said on Friday is it complying with the order and not ending that secondary account.

The legal clash has angered some developers who complain that Apple’s App Store rules are unfair and that the company’s fees are too high. The backlash has also increased antitrust scrutiny of Apple, the world’s most valuable company.

“Apple is asking that Epic revert Fortnite to exclusively use Apple payments,” Epic said in a statement. “Their proposal is an invitation for Epic to collude with Apple to maintain their monopoly over in-app payments on iOS, suppressing free market competition and inflating prices. As a matter of principle, we won’t participate in this scheme.”

Most developers would never publicly criticize Apple because the company’s App Store is such a vital source of users and revenue. Epic is in a different situation because Fortnite is widely used beyond Apple’s platform. Still, losing access to the App Store will likely hurt Epic financially. Since January 2012, Epic mobile games have been downloaded more than 159 million times through the App Store, generating about US$1.2 billion in consumer spending, with roughly US$360 million of this going to Apple, according to estimates from Sensor Tower.

Apple said Epic has repeatedly submitted Fortnite updates that are “designed to violate the guidelines of the App Store.” Apple added that this is “not fair to all other developers on the App Store and is putting customers in the middle of their fight. We hope that we can work together again in the future, but unfortunately that is not possible today.”

The termination of Epic’s main account means that the developer will no longer be able to submit new apps or updates to the App Store. It also means users won’t be able to make in-app purchases inside of Epic’s games and apps, but that customers who have already bought Epic titles will have continued access in their current form.

Apple added that terminating Epic’s developer account is normal practice for such violations. It also said that Epic Games has asked customers to direct frustration over the situation to AppleCare support, creating issues for other Apple customers by clogging up phone lines.