Apple, which is the most valuable company in the world, is facing a range of regulatory battles on both sides of the Atlantic.
Epic Games, the company behind the video game Fortnite, has expanded the territory of its ongoing dispute with Apple by filing a complaint with the European Union.
The iPhone maker first earned the ire of Epic when it took action against the company last August for slipping a new payment system into the iOS version of the hit online shooter.
The move prompted Apple to remove the game – reported to be the most popular in the world – from its App Store and accuse Epic of launching the feature with the “express intent of violating” its guidelines.
It requested a temporary restraining order against Apple to prevent it from revoking Epic’s developer accounts, which it said would cause “irreparable harm”.
The European Commission’s competition regulator, which is also investigating Apple’s mobile payment system Apple Pay and the App Store, confirmed receipt of the complaint to Reuters, saying it would be assessed “based on our standard procedures”.
Epic’s founder and chief executive Tim Sweeney criticised Apple in a news briefing, saying “the 30% they charge as their app tax, they can make it 50%, or 90%, or 100% – under their theory of how these markets are structured, they have every right to do that”.
“Epic is not asking any court or regulator to change this 30% to some other number, only to restore competition on iOS,” added Mr Sweeney.
“What’s at stake here is the very future of mobile platforms. Consumers have the right to install apps from sources of their choosing and developers have the right to compete in a fair marketplace.
“We will not stand idly by and allow Apple to use its platform dominance to control what should be a level digital playing field,” he added.
In its statement, Apple said: “In ways a judge has described as deceptive and clandestine, Epic enabled a feature in its app, which was not reviewed or approved by Apple, and they did so with the express intent of violating the App Store guidelines that apply equally to every developer and protect customers.
“Their reckless behaviour made pawns of customers, and we look forward to making this clear to the European Commission.”
The legal dispute has drawn in a number of sympathisers with Epic Games, with Facebook assisting the firm to provide relevant information on how Apple’s policies adversely impacted the company.
This prompted Microsoft to criticise Apple, saying it “stands alone as the only general purpose platform to deny consumers from cloud gaming and game subscription services like Xbox Game Pass”.
“[Apple] consistently treats gaming apps differently, applying more lenient rules to non-gaming apps even when they include interactive content,” Microsoft added.