Apple Inc. has threatened to prevent Epic Games Inc. from supplying key graphics technology to other apps, as well as removing the firm’s developer account and cutting off its developer tools, in the latest skirmish in a battle over app store fees.

The iPhone maker’s plans were disclosed in a court filing by Epic on Monday.

The disagreement stems from a longstanding Apple App Store rule saying that games must bill their subscriptions and purchases made within apps through Apple’s billing system, which charges a 30 percent fee. On Thursday morning, Epic began offering customers a way to directly buy items for its popular game Fortnite and circumvent the fees. Hours later, Apple pulled the app. Google followed suit later in the day, removing Fortnite from its Play app store.