(Reuters) -"Fortnite" maker Epic Games said on Friday Apple was impeding its attempts to set up a games store on iPhones and iPads in Europe, the latest escalation in a bitter feud over the technology giant's control of the iOS app ecosystem.

Apple ( AAPL ) has twice rejected documents it submitted to launch the Epic Games Store because the design of certain buttons and labels was similar to those used by its App Store, the video-game publisher said.

"We are using the same "Install" and "In-app purchases" naming conventions that are used across popular app stores on multiple platforms, and are following standard conventions for buttons in iOS apps," Epic said in a series of posts on X.

"Apple's ( AAPL ) rejection is arbitrary, obstructive, and in violation of the DMA (Digital Markets Act), and we've shared our concerns with the European Commission," it said.

Under pressure from European regulators, Apple ( AAPL ) had in March cleared the way for Epic to put its own game store on iOS devices in Europe.

Apple ( AAPL ) and the European Commission did not immediately respond to Reuters requests for comment.

Epic and Apple ( AAPL ) have been embroiled in a legal battle since 2020, when the gaming firm alleged that Apple's ( AAPL ) practice of charging up to 30% commissions on in-app payments on its iPhone Operating System (iOS) devices violated U.S. antitrust rules.

Early this year, Apple ( AAPL ) proposed changes to its App Store policies to comply with certain directives of the DMA that came into force in March. The law is meant to make it easier for European users to move between competing services.

(Reporting by Yuvraj Malik and Aditya Soni in Bengaluru; Editing by Shounak Dasgupta and Arun Koyyur)