Fortnite maker Epic Games on Wednesday lodged a complaint against Apple with EU antitrust authorities, deepening its bitter feud with the iPhone-maker over its app store.
Apple and Epic have been locked in a fierce battle over whether Apple's tight control of the App Store, and its 30-percent cut of revenue, is abusive.
The dispute took a dramatic turn in August when Apple expelled Fortnite, one of the world's most popular games, from its app store after Epic released an update that dodged revenue-sharing with the iPhone maker.
Apple does not allow users of its popular devices to download apps from anywhere but the App Store, and developers have to use Apple's payment system which takes its cut.
"We will not stand idly by and allow Apple to use its platform dominance to control what should be a level digital playing field," Epic Games CEO Tim Sweeney said in a statement.
The company said the lawsuit "complements" other legal proceedings it has launched in the United States, Australia and Britain.
The global war over the App Store has widened to Facebook, where CEO Mark Zuckerberg has accused Apple of imposing rules for outside developers that it does not apply to its own services.
This echoes the accusations of Spotify, which also believes Apple has given unfair advantage to its Apple Music service over other streaming services.
Apple firmly rejected Epic's arguments and accused the company of punishing game users when it tried to circumvent the rules of the App Store.
"Their reckless behaviour made pawns of customers, and we look forward to making this clear to the European Commission," an Apple spokesperson said in statement.
Epic "has been one of the most successful developers on the App Store, growing into a multibillion dollar business that reaches millions of iOS customers around the world, including in the EU."
The gripes by Epic, Spotify and others pushed the EU's powerful competition authority to open a series of cases against Apple in June, involving both its App Store and its Apple Pay payment service.
Apple has angrily called the complaints by Spotify and others as "baseless", describing them as sour grapes by companies that do not want to play by the same rules as everyone else accepting its terms.
Apple -- along with Google, Facebook, Amazon and Microsoft -- is also targeted in Europe by new draft legislation, the Digital Markets Act, which aims to limit its digital omnipotence.
But the plan, unveiled in December, is only at the beginning of a legislative process that could last years.