EU antitrust regulators have accused Google of abusing the dominance of its Android mobile operating system in deals with phone makers and mobile network operators.
It follows a year-long inquiry and comes as the technology giant is being scrutinised over its shopping service.
The EU Anti-Trust Commission claims Google has breached competition rules by preventing consumers from “having as wide a choice as possible”.
In a statement of objections, the commission said it was making manufacturers pre-install Google Search and the Chrome browser.
It said it also forced manufacturers to set Google Search as a default service on their devices to gain access to certain Google-owned apps.
The commission added that Google was giving financial incentives to manufacturers and mobile network operators if they exclusively pre-installed Google Search on their devices.
At the same time it was preventing some manufacturers from selling smartphones which ran on “competing operating systems based on the Android open source code”.
The commission said it was concerned these practices could stop other mobile browsers from being able to compete with Google Chrome in the rapidly growing smartphone market.
European Competition Commissioner Margrethe Vestager said in a statement: “A competitive mobile Internet sector is increasingly important for consumers and businesses in Europe.
“Based on our investigation thus far, we believe that Google’s behaviour denies consumers a wider choice of mobile apps and services.”
The statement said regulators also believed the firm’s conduct “stands in the way of innovation by other players”.
Commentators say the anti-competition charge could hit a key money-spinner for Google, which is a subsidiary of Alphabet Inc.
It made around $11bn (£7.6bn) from ad sales on Android phones with Google apps such as Maps, Search and Gmail last year.
Google is already being probed for promoting its own shopping service in internet searches at the expense of rivals.
That case, which has dragged on since late 2010, culminated last year with the European Commission filing antitrust charges against Google.
In a statement, Google’s Senior Vice President & General Counsel, Kent Walker, denied the company attempted to stifle competition.
“Android has helped foster a remarkable — and, importantly, sustainable — ecosystem, based on open-source software and open innovation,” the statement said.
It added: “We look forward to working with the European Commission to demonstrate that Android is good for competition and good for consumers.”