The European Commission told Apple on Friday that it had violated European Union (EU) competition law by abusing its dominant market position.

“Apple abused its dominant position for the distribution of music streaming apps through its App Store and distorted competition in the music streaming market,” European Commission Executive Vice-President Margrethe Vestager, whose portfolio includes competition issues, told a press conference.

According to the EU executive body, the tech company distorts fair competition by making compulsory its own application purchasing system for iPhone and iPad users while charging 30-percent commission on downloads from other developers.

At the same time, the company restricts the applications ability to inform their users about cheaper subscription options outside the App Store.

If music streaming providers don’t accept these terms, “they lose access to Apple device users for paid subscriptions,” said Vestager.

The scrutiny was triggered by a complaint of music streaming app Spotify, which argued that the company directed users towards its own Apple Music app by making competing services more expensive.

Since the App Store hosts 1.8 million applications, its “rules are a concern for many app developers beyond music streaming because they depend on Apple App Store as a gatekeeper to access users of Apple’s iPhones and iPads,” Vestager said.

“This significant market power cannot go unchecked,” she added.

In the next stage of the procedure, Apple can reply to the objections of the European Commission.

If the EU body does not accept its reasoning, it can impose a fine on the tech company for distorting the market.

In 2016, the European Commission imposed a €13 billion ($15.7 billion) fine on the US firm for evading taxes in Ireland.

The decision was annulled last year by the European Court of Justice, but the EU executive body filed an appeal.

Maintaining fair competition in the EU’s internal market is one of the few exclusive competences of the bloc. It allows the European Commission to decide on state aid rules and fine companies for breaching EU law.