Google has been issued formal antitrust charges over claims that it abuses the dominant position of its Android operating system.
The European Commission (EC) sent a statement of objections to the tech firm, alleging that it has breached EU competition law.
Google is accused of placing onerous requirements on firms using Android and stifling competition.
It said Android was "good for competition and good for consumers".
Kent Walker, Google's senior vice president and general counsel, said:
"Android has helped foster a remarkable and, importantly, sustainable ecosystem, based on open-source software and open innovation. We look forward to working with the European Commission."